


Sirenic Lullaby

by CassondraWinchester



Series: Destiel A/B/O [7]
Category: Supernatural
Genre: Alpha Dean Winchester, Alpha/Beta/Omega Dynamics, Anal Fingering, Anal Sex, Creature Fic, Fairytale elements, Fluff and Smut, Hand Jobs, Happily Ever After, Kidnapping, Knotting, M/M, Mating Bites, Mating Cycles/In Heat, Omega Castiel, Rimming, Siren Castiel, True Mates, merfolk
Language: English
Status: Completed
Published: 2018-08-18
Updated: 2018-09-07
Packaged: 2019-06-29 06:16:30
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 7
Words: 52,892
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15723660
Author URL: https://archiveofourown.org/users/CassondraWinchester/pseuds/CassondraWinchester
Summary: Omega Mer-Sirens finally reach maturity to sing at the magic age of thirty. And when you live for hundreds of years, it’s not a long time to wait. Although Castiel is at odds with some of his clan’s teaching and traditions, he is ready for his Rite of Passage. His death song is beautiful, and will no doubt woo a Alpha Human to a peaceful grave.But, in the midst of his song Castiel discovers that the Alpha Human he’s chosen is, in fact, his true mate! How can Castiel save his mate from plunging into the sea in time? Can a Siren and a Human fall in love? Can the Gods truly protest when they have marked them as true mates?





	1. Chapter 1

**Author's Note:**

> Huge shout out to Hidden by the Trench Coat for hosting this Fairytale challenge. I had such a blast writing this story. 
> 
> Also big thanks to lotrspnfangirl and Ani-make-me-girl for beta’ing this chapter, and zephyrchrysalis for Alpha reading and surprising me with some art as an early birthday present!
> 
> Oh and FYI when you get to Triton in this fic picture Cain. I had him in mind when I wrote the character.
> 
> Now, go forth and read! :)

  


  


  


**“We drift on a**  


**chartless, resistless sea.**  


**Let us sing when we can,**  


**and forget the rest.”**  


**H.P. Lovecraft**

  


  


“Daddy, Papa, tell us a bedtime story.”

“And what kind of story would you like to hear?” Dean asked their daughter, Cordelia, as he watched Castiel usher both her and her twin brother, Dylan, to their nest. He smiled as he watched his family; Cordelia was the spitting image of Castiel with her dark hair and big blue eyes, whereas Dylan looked like a mini Dean, right down to the freckles that dotted his face.

“The one about how you and Papa met!” The twins answered in unison.

“Really?” Dean mock groaned from the doorway before making his way further into the room. “With how many times you two have heard that story in your nine years of life, you haven’t tired of it yet?” 

Cordelia shook her head, her long raven locks swishing from side to side. As she lay down in the nest, she motioned for her father to join her. “It’s romantical, Daddy!” 

“And magical,” Dylan added as he looked up at his papa, his bright green eyes shining.

“That it is,” Castiel whispered in agreement as he ruffled his son’s rich honey colored hair.

Dean chuckled softly as he settled down beside his daughter, grinning as Cas did the same behind their son. Once the four of them were settled in the nest, Dean glanced over to his mate, giving him a look of pure love and adoration before he turned his attention to their children between them. He cleared his throat and began.

  


Castiel sat perched on the window bench in his bedroom, his favorite spot in the entire castle. Not only did he have the peace and quiet that he often craved, but also the best view of all of Atlantis.

His tail fin swished back and forth nervously as he thought about tonight and what it would bring. Castiel’s fingers instinctively reached up and clutched the necklace around his throat. He tried to find comfort in the beautiful multi-colored shell choker twined in seaweed with an enchanted black pearl resting in the center.

It was a gift from his mother, the last thing she gave him while on her deathbed.

Castiel let out a deep sigh. Gods, he wished she was here. She could hold him, run her fingers through his hair like she used to when he was just a youngling. She would tell him everything would be fine, it was his time, after all. She would tell him it was a gift from the Gods to be an Omega, to be born with the wondrous abilities of a Siren. He had a voice so enchanting it would one day, not only find him a strong mate who he could comfort and seduce with a simple song, but also enthrall any land born Alpha to follow his whims, even if it brought about their own demise. The sultry tone of a Siren’s song brought about death and destruction to any mortal Alpha unfortunate enough to hear their enchanting melody. 

They sing their own personalized death song with pride. No two Siren songs are the same, each one hauntingly beautiful in its own way. Their tune is unforgiving and lures unsuspecting human Alphas to a watery grave. That was just the way of the Siren, and now that Castiel’s life had marked its thirtieth year, it would now to become his way. His time had come to start singing Alphas to the sea, and no Alpha will be powerful enough to resist his death song.

But... will those Alphas deserve to meet that kind of fate? And what about all those who came before, the ones his fellow Omega Sirens had sang into an early resting place? There were both good and bad land Alphas, just as there were good and bad Mer-Alphas. Castiel knew both counts from personal experience. 

Being young and a crown prince, son of the powerful King Triton, had not been as easy as most would think. He had been ridiculed by plenty of Alphas over the past thirty years, received countless false declarations of love from those wanting his hand for power or for bragging rights. The ability to claim they had bedded the Omega Siren son of the mighty King Triton would grant them authority and influence that they otherwise lacked. They told their false tales of how they had made the prince sing for them. But Castiel didn’t care, nor was he naïve or interested in any of them. 

Castiel had known from the time he was a youngling that when the time came for him to mate, his father would find him a suitable Alpha of equal power and stature. So, Castiel just let them talk, ignored the whispers of those Alphas calling him stuck up and prudish. None of it mattered to him anyway. Despite the odds being against him, he was holding out hope that his father would one day find his true mate, the Alpha that was made only for him. He would gladly sing songs of seduction and comfort for his true mate.

As far as mortal Alphas went, many of them pollute the Merfolks homes with their filth with no regard or care to what they’re doing. Their trash, snares, and nets have killed plenty of his kin. Not to mention the one who killed his mother. That Alpha definitely deserved hearing the sultry tones of his Aunt Rowena. Still, he couldn’t help but wonder about all the others that had or will hear a siren’s songs. Were they all deserving, too? Or were some just in the wrong place at the wrong time?

  


  


As Castiel watched a stingray slowly swim by his window, he couldn’t help but to wonder if his mother ever had doubts about the Alphas that heard her song. His eyes brimmed with tears and he blinked them away. He wished she could have been here today so he could voice his fears about singing to good Alphas undeserving to meet that kind of fate. He wanted to ask her every question that had been eating away at him since he first laid eyes on his intended target for his Rite of Passage.

He rubbed the smooth black pearl between the tips of his fingers as his mind filled with images of his mother’s smile, her kind blue eyes, and long flowing golden hair that matched her tail and shelled corset. He couldn’t help but to think back to that fateful day twenty years ago. He’d been a youngling of only ten at the time, without a care in the world. He was frolicking and playing with his friends, chasing the dolphins around the courtyard when his father had found him and delivered the most devastating news of his young life. His mother, Queen Cordelia, had been caught off guard and speared by a human while sunning on the rocks. It was a fatal blow, not even the most powerful Sea Enchanter could heal her wounds, and she was asking for him to say her final goodbye. 

Castiel remembered swimming back to the castle as fast as his little tail would allow. The way he paused outside his parent’s bedroom until his father gently ushered him in. How frail and vulnerable his mother looked as she lay there dying, nothing like the fierce force of nature he’d known her to be. But most of all, he remembered their final conversation…

_“Castiel,” Cordelia whispered as she turned her head to the side and gave her son a small smile. “Quit lingering there in the doorway and come sit with me.” Castiel hesitated, looking from his father to his older brother’s heartbroken faces._

_“Go on,” Gabriel whispered as he placed his hand on Castiel’s lower back. “Father and I have already said our goodbyes.”_

_Castiel nodded slowly, his tail slowly swished up and down as he made his way over to his parent’s nest and settled down by his mother. “How are you feeling?” Castiel shook his head and sighed as tears filled his eyes. “That's a stupid question.”_

_“No, baby, it’s a logical question.” Cordelia reached over and took her son’s hand in hers, giving it a gentle squeeze. “I feel at peace.”_

_“How?” Castiel voice quivered. “How can you be at peace with dying? You’re still so young Momma, you should have many years left with us.” He hiccupped as tears streamed freely down his cheeks. “It’s not fair.”_

_“Oh, sweetheart...” She reached up and gently thumbed away his tears, flinching at the pain in her stomach where the spear had impaled her._

_“Lay still,” Castiel carefully eased her back down into the nest. “You shouldn’t be moving too much.”_

_She waved away his concerns and continued, “Life isn't always fair, Castiel. Sometimes bad things happen to good people. That’s just the way it is.” Cordelia took his hand again. “As to why I’m at peace?” She smiled softly at her youngling, “I lived and loved to the fullest. I spent many wonderful years with your father, had two amazing boys.”_

_She smiled fondly as she thought of her kids. “Gabriel and you, my youngest, my baby boy.” Cordelia reached up and pinched his cheek lovingly, grinning tenderly as he mumbled and flushed scarlet. “You two have made my life complete in ways I never knew were possible. I couldn’t have asked for more in this life.”_

_“I love you,” Castiel whispered as he ran his fingers through her golden hair. “I love you so much, Momma.”_

_“I love you too, my sweet, sweet, child.” She smiled up at him before pointing over to the small nestside table. “Could you please open the top drawer and hand me the jewelry box inside?”_

_Castiel nodded and did what he was asked, letting his fingertips graze against his mother’s as he passed the worn, pink coral box that was adorned with a variety of shells and sea glass that he and Gabriel had collected for her over the years._

_“It’s beautiful,” he whispered as he watched her trace one of the larger tiger moon shells with a faraway look in her eyes._

_“It is,” Cordelia hummed in agreement. “Now,” she looked up into his sad eyes, “before it was just a plain pink box, but look at the wonder you and your brother made of it.”_

_Her gaze flitted back down to the shell she had been reverently caressing the entire time she spoke. “I still can remember who gave me what shells and which piece of sea glass that decorate this box. This one right here,” she tapped the tiger moon shell that was still under her fingertips, “you gave to me when you were five. I remember having a fit when you told me you found it down by the shark’s nests. I couldn’t believe you’d gone down there all alone. But then again,” she looked fondly at her boy, “you’ve always been a very brave and curious child, Castiel. You take after me I suppose.” She huffed a small laugh that quickly turned into a violent coughing fit, the jewelry box sliding off her lap and into the small space between them._

_“Momma!” Castiel’s eyes widened as he saw a bright patch of crimson spread across the white dressing wrapped around her lower abdomen where flesh met tail. His breath hitched as his gaze snapped up to her face where spots of blood now painted her pink lips. Castiel’s hand shook as he reached up and wiped it away with his thumb, unable to stomach the sight of it and what it meant._

_“I can feel it,” she whispered. “I don’t have much time left.”_

_“Please don’t say that,” Castiel cried out, his shoulders trembling. “I’m not ready for you to go!”_

_“I need you to be brave for me.” Cordelia reached out and gripped both of his hands tightly in hers, centering them both. “I need you to be the brave boy I know you are. Can you do that for me?” She waited for his curt nod before continuing, “Good.” She gave his hands one final squeeze before letting them go. With trembling hands, she picked the jewelry box back up and opened the lid, revealing hidden treasures that had been given to her by her husband and her boys over the years._

_Cordelia gave him a sly smile before pulling open a secret compartment hidden in the top of the box, revealing a beautiful necklace. She took it in her hands before closing the jewelry box and setting it aside. Cordelia cradled it in her palms as she met her son’s curious gaze. “Here,” she thrust her hands towards him for Castiel to take it, “I want you to have this.”_

_“It’s yours, Momma.” Castiel shook his head. He’d seen the way she looked at the necklace. It was clearly something special, especially since she had kept it guarded by a secret compartment all this time. “I can’t.”_

_“You can, and,” Cordelia grabbed his hand and opened it, placing the necklace in his palm before gently closing his fingers around it, “you **will**. It’s my gift to you, Castiel.”_

_He slowly nodded as he opened his fist and looked at the choker resting in his palm. Magnificent shells of multiple colors and varieties were woven intricately between bright green seaweed. Pink Cardium Cardissa Hearts rested beside Strawberry Tops, Astraea Stars and tiny Conch Shells were carefully netted in the perfect spots. The placement of each shell seemed so well thought out and flawless, but what really caught Castiel’s eye was the black pearl resting perfectly in the center._

_“It’s so beautiful,” Castiel murmured in awe as his fingers caressed the inky pearl. He reached up and wiped a tear away before looking into his mother’s eyes. “Thank you.”_

_“Take good care of it, Castiel. This necklace is no ordinary necklace,” she whispered as she gingerly shifted closer to him._

_Castiel’s brows furrowed as his gaze darted back down to it. “What do you mean?”_

_“Well, your Aunt gave that necklace to me after I had you, and she told me within that pearl,” Cordelia reached over tapped it, “holds one wish to the owner of the necklace.”_

_“Auntie Rowena, the Siren Sea Witch, gave you this?”_

_Cordelia tutted faintly as she reached up and tapped her son's nose. “You know she’s hates being called that.”_

_A smile spread across his lips as he thought of the age old argument between his father and aunt. Triton had always referred to her as the Siren Sea Witch, and Rowena would flip her long red hair over her shoulder as she corrected him, “Really, Triton? Sea Witch makes me seem like an old hag. I prefer Sea Enchantress, much more fitting, you know?”_

_“Why are you smiling?” Cordelia asked, drawing him from his musings._

_Castiel’s smile grew as he met her eyes. “Just thinking about father and Auntie Rowena.” A giggle escaped from him as she grinned as well. “They’re pretty funny when they’re together.”_

_“That they are, sweetheart.” The smile slid from her face and was replaced with a much more serious expression. “Castiel, keep this necklace safe, wear it always. I feel in my heart one day this necklace, and the wish within, will change your life.”_

_Cordelia took the necklace from his hands and beckoned him closer so she could place it around his neck and fasten the clasp. “There.” She ran her fingers along the shells and placed her palm over his heart. “Promise me. Promise me, Castiel, that you will keep this safe, always.”_

_“I promise, Momma,” Castiel whispered as he placed his hand over hers. “Can I ask you something?”_

_“You can ask me anything,” she replied as she removed her hand from his chest and let it fall to her side._

_“How come you never used the wish?” He queried as he drew his bottom lip into his mouth and waited for an answer._

_“I never felt the need.” At his perplexed look, Cordelia continued, “I had your father, Gabriel, and you. Castiel, I couldn’t have asked for more. No wish could’ve made me happier than I was already.”_

_Another coughing fit wracked Cordelia’s body and crimson oozed past her lips and down her chin. When it subsided and Castiel had wiped away the blood staining her face, she met his eyes with a somber expression. “The time has come for me to say goodbye to you.”_

_“No,” Castiel shook his head as he began to cry again, “no, I’m not ready for you to leave me.” He reached for the necklace. “I want to use my wish to save you.”_

_“Castiel,” she reached up and stopped his trembling hands pulling at the necklace, “my time here has drawn to an end. I’ve accepted it, my son, now you need to. This wish,” she held the pearl in her weak grip, “is not meant for me. It’s meant for something greater. You will know what when that time comes.” Cordelia twined her tail around his. “I love you, my sweet boy.”_

_“I love you, too, Momma.”_

Castiel blinked back the tears from his eyes and wiped his cheeks with the back of his hand as he settled closer to the window. He pressed his forehead against it, focusing on the younglings swimming and playing with a pod of dolphins in the courtyard down below. He watched them, waiting for the remnants of pain to bleed out into the current around him. 

He focused on the younglings, studied their movements until he recognized the game they were playing. Then Castiel found himself smiling. What he wouldn’t give to be that young and free again, to not have priorities or a care in the world. Despite his gloomy mood, he found himself waving back when a little girl swam by his window laughing and waving both her hands at him, while two young boys chased after her with large grins on their faces.

A ruckus in the hallway drew Castiel’s attention from the younglings to his door moments before it burst open.

“Castiel!” Gabriel swam into his room out of breath, and following closely behind him was a sea lion pup. “Your damn pet has been in my room again chewing up my stuff!” He shot a glare at the pup. “You need to keep a better eye on that lil’ shit.”

  


  


“Finn.” Castiel smiled and shifted on the window bench as he motioned for the pup to come to him. A happy bark sounded loudly as the sea lion quickly swam over and joined Castiel, laying his head in the Siren’s lap. Castiel ran his fingers through the short thick fur down the slope of his back. “Have you been getting up to no good this evening? Have you been messing about in Gabriel’s room, _again_?” Castiel scritched Finn beneath his head, fixing him with a stern look. “You know he doesn’t like that.” 

Finn looked up at Castiel with big brown innocent eyes before flitting his gaze over to Gabriel, his innocent eyes now narrowing as he huffed at the Alpha Merman.

“Don’t be so dramatic,” Castiel rolled his eyes at his brother before leaning down and pressing a kiss to Finn’s snout. “He’s just a curious little pup, that’s all.”

“Speaking of curious,” a wicked smirk spread across Gabriel’s lips as he flitted further into the room and settled down in Castiel’s nest. “I’m _curious_ if my lil’ bro is ready for his Rite of Passage ceremony? Are you ready to sing your death song for the very first time tonight.” 

“It’s my time,” Castiel whispered as he gnawed on his bottom lip.

“Hmm,” Gabriel quirked a brow, “Okay.” The Omega watched his brother’s mischievous expression turn serious. Castiel could tell he was debating on pressing him further on the half-assed answer he had given. Instead the contemplative look melted back into one of playfulness as Gabriel waggled his brows and changed the subject. “Well, I wanna hear all about the Alpha you have chosen to be your first sacrifice to the sea.” 

Gabriel dug his amber tail into the sand, making himself more comfortable before continuing, “I’ve noticed that you’ve been going up top every night for over a month now. What were you doing, swimming around and sniffing until you found the one Alpha that caught your fancy?”

“No,” Castiel huffed a small laugh and shook his head. “That’s not how it works, Gabriel.”

“I’m not an Omega, nor a Siren, so I have no clue how it works.” The Alpha rolled over onto his stomach and propped his elbows up before placing his chin in his palms. “So why don’t you tell me.”

“It’s hard to explain,” Castiel moved to the edge of the window bench and leaned forward, whispering an apology when it roused Finn from a deep slumber.

“Well,” Gabriel shrugged nonchalantly, “just give it a try, I’m pretty smart.”

“Alright,” Castiel snorted. “I’ll make sure to dumb it down some, you know, just to make sure you understand.” He scratched behind his pup’s ear flaps laughing softly at the affronted look on his brother’s face from the little jab towards his intelligence. 

“Hardy har-har, you’re a regular comedian, little brother. Now,” Gabriel made a ‘come on’ gesture with his hands, “get to explaining.”

Castiel took a deep breath and began, “Sirens, we can just tell if someone is an Alpha. We don’t need to scent them, we just _know_. They have this aura about them, it draws us to them, makes us want to sing to them.”

“And this Alpha you have chosen,” Gabriel wriggled in the nest, settling deeper in the sand. “You were drawn to him because of his aura, no scenting needed?”

“Yes,” Castiel nodded, “I was. From the moment I saw him over a month ago, his aura instantly intrigued me.”

“How romantic,” Gabriel mock sighed dreamily as he batted his eyelashes dramatically. “Tell me all about him.”

“Not much to tell,” Castiel muttered as he looked over his shoulder and out the window just as a sea turtle whizzed by.

“Come on, Castiel,” Gabriel whined as he swished his tail enthusiastically. “I wants deets on this land Alpha that makes you wanna sing.”

“Fine,” Castiel sighed as he turned his attention back to his brother, knowing Gabriel would just continue to annoy him until he gave up some kind of information. “He bought the seaside cottage on the north side of the caves, close to the rocks where I like to sun. That’s where I was when I first saw him.” The Siren’s lips quirked up into a small smile. “I was lying on the rocks singing as I watched Finn swim and play when I heard a noise on the beach. I perched up higher on my rock so I could get a better look at the bank, and there he was, sitting at the shoreline barefoot, letting the water lap up over his feet.”

Castiel’s smile grew as he thought about the first time he saw the handsome human. “His hair is the same shade of a Fighting Conch Shell and he has eyes as bright as turtle grass.” He let out a soft sigh remembering. “That day, I laid there silently on my rock, and I watched as he sat in the sand with his jeans rolled up to his ankles.” He looked over at his brother, “He had a childlike grin on his face every time the water tickled his bare feet. And every now and again he would close his eyes and let his head fall back. And the sun kissed his face. He is quite beautiful.” Castiel shook his head, clearing the vivid memory of that day away. “The moment I laid eyes on him I just knew, Gabriel. I knew I _needed_ to sing for that Alpha.” 

“Wow,” Gabriel sat up and met his brother’s eyes. “That sounds intense. I mean being drawn to someone and feeling a _need_ that deep. Is it always like that?”

“I wouldn’t know,” Castiel shrugged. “I’ve never felt it before now.”

Gabriel nodded and they both fell quiet, each lost in their own thoughts. Their calm reflections were shattered when the evening bells chimed throughout Atlantis. Gabriel gave Castiel a small smile before swimming over to join him on the bench. “C’mon, little bro, it’ll be dark soon. It’s almost time.”

“Yeah,” Castiel whispered as he leaned in closer to his brother, Finn huffing when the Siren jostled him awake again. “I know.”

“Sing with pride,” Gabriel smiled as he twined his tail around his brothers. “No Alpha will be able to resist you.” He gave Castiel a comforting squeeze with his tail before untangling and swimming toward the door, pausing just outside of it. “If you ever need me, you know I’m here for you, right?”

“I do,” Castiel nodded. “Thank you, Gabriel.” 

The door closed with a soft snick. Castiel kept his gaze on it for another few moments before he shifted his position and laid his forehead against the window. Finn barked softly and shuffled closer, laying his head back in the Siren’s lap. Castiel immediately started stroking the pup’s side, finding comfort in the closeness of his aquatic friend. He watched as all the younglings started making their way home, the sun would be setting soon and playtime was over.

Castiel watched the ocean life mill about around him as the waters grew darker and darker. When the Moon Jellyfish began to move about lighting up the sea in a variety of pinks, greens, and purples, like ghosts through the water, he knew the time had come. There was a pull inside him calling him to the surface, calling him to the land Alpha he had chosen. 

The Siren’s Rite had now begun. It was time for him to sing his death song, time to serenade his first Alpha to the sea.


	2. Chapter 2

**Notes for the Chapter:**

> Big thanks to Ani-make-me-girl for beta’ing this chapter, and zephyrchrysalis for Alpha reading and providing art.
> 
> Enjoy!

**“From the shore the ocean is**  


**forever. It’s a beautiful,**  


**dangerous place. Music is tied to**  


**the sea, born from the struggle,**  


**looking for hope. Because hope**  


**belongs in dark places.”**  


**Jon Foreman**  


  


  


Dean stood on his back deck leaning against the railing as he stared out at the serene ocean waters. He inhaled a deep breath, taking the salty sea air into his lungs and a sense of calm instantly washed over him. He was filled with a sense of peace he hadn’t even realized had been missing from his life until he set foot on the sandy beach of his new home six weeks ago.

He thought back over the past year. He’d become restless, no longer happy with his large house, top rated electronics company, and the vibrant night life of the big city. He’d started to feel hollow, a deep ache churned in his chest. The foods at his favorite restaurants started tasting bitter and left him unsatisfied. The extravagant business trips began to bore him, and no amount of money or power could fill an ever growing void.

Then the dreams started—dreams of white sands and indigo oceans, of dark hair and cerulean eyes. After numerous nights waking up in a cold sweat with the feeling of something that was just out of his reach, he made the most impulsive decision of his life. And within five weeks he’d sold his home, his business, and used the money to follow his newfound desire of buying a house by the ocean. 

His brother, Sam, thought he’d lost his mind a little bit. His friends and associates just thought he was burned out and would sit on a beach for a few months before coming back to real life as they called it. And his Uncle Bobby, just thought he’d gone plumb loco—his words.

But, in the month and a half that he’d been settled in his small cottage home on the sunny beach of Nassau he'd felt more complete and more content than he had in forever. The ache had lessened and the void had stopped expanding. Though he was more satisfied than he’d been in a long time, there was still one major thing missing—something his dreams reminded him of every night. He craved that dark hair and those blue eyes, he longed for the one thing that would make his life absolutely perfect. He hungered for a mate. 

Dean sighed as he pushed off the rail and walked down the porch steps and onto the sand. There was no doubt in his heart that he’d been drawn here by his inner Alpha, this seaside home had called to him, but _why_? 

Why here?

Why now?

The Alpha let out a deep sigh as he shoved his hands in his pockets and strolled along the beach. Dean listened to the waves crashing in the distance, the noise almost deafening in the serene night, the sound pulled him closer to the shores. He looked out at the ocean, the dark water glittered under the full moon. He cleared his mind as he let his feet carry him to some unknown destination.

A small smile broke out across his lips when he realized where he ended up, the rocky caves at the edge of his property. He wasn’t surprised though, this spot called to his inner Alpha as much as the little cottage had. The waters were relatively still, small waves lapped up onto the shore as Dean bent down and picked up a stone, he rubbed it between his thumb and forefinger the rock smooth from years of wear in the ocean. Dean drew his arm back before swinging forward with a little flick of his wrist, he watched as the rock flitted across the surface before sinking into the dark water.

Memories of the first time he had walked down here swam to the forefront of his mind.

  


  


_Dean let out a relieved sigh as he unpacked the last box, stacking the pots and pans on the kitchen counter. He broke down the box, stacked it in the recycling bin, and proceeded to put away his cookware. He stretched and popped his back after he placed the last of the baking trays in the cabinet by the stove. He grinned as he took a look around at the progress he’d made over the past few days, everything was now in its rightful place. He was home._

_Dean wiped the sweat from his brows in the crook of his elbow before grabbing a beer from the fridge. A cold beer had been well earned after all that hard work. Just as he was ready to flop down on the couch and watch a movie, he heard the gulls calling outside. All thoughts of MovieStream were quickly abandoned as he swung open the back door and made his way down to the beach. He hadn’t bought this place to spend his time in doors vegging out on the sofa watching TV. He could have easily done that back in the states in his big rambling house with the wall sized plasma-screen._

_He felt lighter as he felt the warm sand under his bare feet. He wiggled his toes, loving the tickly sensation the little grains provided. He glanced out at the ocean, it was magnificent, a thing of allure and danger. The waves crashed against the shore in an hypnotic rhythm. As he stared out at the vast expanse of its grace, the only word that came to his mind was magical. A warm breeze kicked up around Dean as he continued to gaze at the neverending expanse of blues and greens and violets. Taking in a deep breath, he could smell the brine in the air. In that moment he truly felt at home._

_He walked closer to the shoreline letting his feet dig into the wet sand as he wandered down the length of the beach. He stopped by a large clusters of rocks, some close to the shore, others spread out further into the ocean. Waves crashed against the rocks along the bank, foam spreading across the sand before being swept back into the sea again._

_Dean rolled up his jeans as far as they would go before plopping down in the sand, knees drawn up. He grinned as the water spread across his feet, he knew his jeans were going to end up getting soaked through but in that moment he couldn’t find it in himself to care._

_As he sat there, the warm water rolling up to meet him, he heard something off in the distance, a voice. He shook his head, sure his mind was playing tricks on him, but a few minutes later he heard it again. He leaned forward resting his arms on his knees and listened closely._

_Singing._

_Someone was singing._

_And that voice, it was deep, enchanting, and definitely male. It made his heart race and his inner Alpha purr. He sat quietly, waiting for someone on a boat to come past those rocks, but no one came, and shortly after it had started the singing had stopped. He was left wanting more. He stayed there until the sun went down hoping to hear that voice again, or better yet catch a glimpse of the person to whom it belonged._

_Neither happened, and as he walked back to his cottage Dean was left wondering if maybe it had been in his mind after all._

  


  


Dean sat on the cool sand, far enough back from the water so the waves wouldn’t reach him. He crossed his legs and reached out in front of him, picking up a shell that was glistening in the moonlight. He cleared the sand from all its crevices before twisting it around in his fingers. It was beautiful, spiraled and white with light brown spots of different shapes and sizes. He placed it in his pocket to take home and add to the growing collection of shells he’d gathered from this area.

Every evening Dean would find his way back to this spot, guided by his inner Alpha and deep down he knew he was searching. He longed to hear singing beyond those rocks again and he hoped the person that voice belonged to had the blue eyes and dark hair from his dreams. So again, it was really no surprise to him that he ended up there again tonight.

He could spend hours on end sitting on the shores picking through shells, waiting, yearning, for someone he was unsure even existed. Every night when he returned home alone, no closer to figuring it out, his inner Alpha whined pitifully, missing something he’s never had. Tonight would seemingly be no different.

When his fingers began to cramp from digging in the sand for so long, he decided to call it a night and head back home. He rocked forward and pushed himself up onto his feet, taking one last look out at the ocean wishing to see something, anything. When all that stared back at him was dark rippling waves he turned to walk away. 

He’d taken two steps when he faintly heard something. Dean paused, that voice, it was the voice he’d been longing to hear again for what felt like an eternity. And it was singing the most alluring sound, like a lullaby, the words drifted to the shore, carried by the wind, to his ears.

**“When I want you, I don't have to raise my voice.  
When I call you, you know you haven't got a choice.  
When you hear me, you better come without delay.  
Hear me singing, honey, won't you come and play?”**

Dean swayed slightly before spinning back around and scanning the waters for the owner of that sultry tone. He didn’t have to look long, about a football field from the bank a man was perched on the rocks looking directly at him. Illuminated by the light of the moon he could see the dark hair. He could only hope that the man’s eyes were the blue of his dreams. 

The Alpha stumbled forward wanting to get a better look.

**“Coooome on.”**

The man lifted his hand motioning Dean forward. The Alpha nodded agreeably because nothing seemed like a better idea in that moment than getting closer to him. Dean staggered forward only stopping when the cool water lapped up and into his shoes. 

**“Succumb, surrender to me.  
Throw yourself into my sea.  
I'm waiting here with my arms open wide.  
Come to me, darling.  
Come inside.”**

In a daze Dean removed his shoes. At the man’s pleased nod and sensuous hum of approval the Alpha continued to rid himself of his confining clothes, leaving himself bare to the stranger’s appreciative gaze. As Dean tossed his last piece of clothing onto the shore he started to wade further into the water towards the captivating stranger. 

**“Don't you want it?”**

God Dean did, he had never wanted anything more in his life than to reach this man. His fingers itched to caress him, hold him—his lips burned to kiss him, to make him his.

**“You know it's gonna feel so good.  
You can't stop it—you wouldn't want to if you could.  
And I know it, I've got you wrapped around my thumb.  
When I give you my sweetest oblivion.  
Coooome on.”**

Dean drudged onward, the water splashing against his bare chest. His gaze was locked on the man singing to him so sweetly. As he came closer her grinned at the deep blue eyes locked on him. Not once did he look down at the waters rising up around him, too enchanted by the deep azure gaze beckoning him to come. He felt the coldness of the ocean. He tasted the brine on his tongue, smelled it all around him, but nothing was going to stop him from reaching this mysterious man.

**“Succumb, surrender to me.  
Throw yourself into my sea.  
I'm waiting here with my arms open wide.  
Come to me, darling.  
Come inside.”**

The further out Dean traveled the deeper the water became until he was no longer able to touch bottom and had to swim. As the Alpha glided closer his eyes raked over the beautiful stranger. His blue eyes were shining, his toned body glowed as he swayed on the rocks and he sang his enchanting melody, never breaking eye contact with Dean. The man’s words continuing to drift on the breeze, pulling the Alpha in by an unseen strand of harmony that poured past his plush lips. 

**“Give in, give over to me.  
Drown yourself, satisfy your need.  
Nothing to fear, I've got nothing but time.  
Come to me, darling.  
Come inside.”**

As Dean’s gaze drifted lower down the man’s chest his breath caught, just underneath the stranger’s belly button flesh melded into scales. Where legs should have been there was a long serpentine like tail that tapered down to a point and branched off into two large paper-thin fins spread out on either side. The creature’s iridescent tail shone in the full moonlight, rippling colors from inky black to a variety of blues that would make the ocean itself jealous.

**“Little Alpha, little fool,  
you better heed the golden rule.  
Do unto others just as you,  
would like to have them do to you.  
You think you can just walk away,  
but no, it doesn't work that way.  
See, once you're mine you'll always be,  
I never give anything for free.”**

Deep down in the recesses of Dean’s foggy brain he knew he should be terrified, that he should swim back to the shore and run far far away from this creature. He physically couldn’t though, his head felt hazy, and the intense need to reach this unknown soul pulsed through his veins with such intensity and determination that if he’d been of sound mind it would’ve scared the shit out of him.

**“Give in, give over to me.  
Drown yourself, satisfy your need.  
Nothing to fear, I've got nothing but time.  
Come to me, darling.”**

Dean’s arms and legs grew tired, the spray of the sea splashed against his face and made his eyes sting and fill with tears. The Alpha’s whole body began to feel like an anchor dragging him under. He fought against it, fought against the pain and his tired limbs. He couldn’t give up, not now, not when he was so damn close, almost able to reach out and touch the individual he’d been dreaming about for so long.

A large wave crested and dragged Dean under just as he extended his arms to grab the rocks. His lungs filled with water but he wasn’t afraid, he could still hear the rapturous song being sung just for him and it brought him a sense of tranquility. Deeper and deeper Dean fell, further into the darkness of the ocean that was intent on swallowing him whole.

  


  


**“Come inside.”**

As the last notes of the Siren’s death song spilt past his lips like rich wine the wind changed its course and blew the most heavenly scent in Castiel’s direction. It smelled of earthy island driftwood and warm amber, like love and comfort, like home and _true mate_.

“No,” Castiel’s eyes widened as he looked around desperately for the Alpha. “No, no, no,” he shook his head before taking a deep breath and diving into the sea to search for his mate.

The Siren swam fast and frantically, following the current as he dove deeper, hoping it wouldn’t be to late when he finally found his Alpha. Out of the corner of his eye he saw a hand stretching upwards. Castiel immediately descended, reaching out he grasped his mate’s hand in his and pulled him up. The Siren he clutched the Alpha’s wrist and felt the dull slow thud of the human’s heartbeat. Castiel looked skyward, he was no longer able to see the surface layer, they were too deep. There was no way he could swim fast enough that he’d be able to make it back to surface before his Alpha perished. The Siren’s heart ached at the thought of watching his true mate die before his eyes, even more so knowing it was his fault. 

There had to be something he could do to save his Alpha. Anything, he would do _anything_ if it meant a chance that his mate would live. Castiel’s mind raced, filling with numerous thoughts and ideas. He was overwhelmed, unsure of what to do, when a voice, a memory from the last moments he spent with his mother, quieted the racket inside his head.

 _“This wish is not meant for me. It’s meant for something greater. You will know what when that time comes. I love you, my sweet boy.”_

Castiel reached up and touched the pearl briefly before gripping his Alpha’s shoulders and yanking him flush against his chest. The man’s body was pliant and lifeless as he pressed his lips to the Alpha’s releasing the breath he’d taken before diving in after him, he hoped it would be enough oxygen to keep his mate alive for a while longer. 

The Siren moved back, his hands scrambled for his necklace, quickly undoing it and refastening it around the Alpha’s throat with the same amount of urgency. He pressed his hand to the black pearl as he whispered, “Please save him. I wish to save my mate.” 

Heat spread across Castiel’s palm, emanating from the pearl. The Siren gasped and flinched back, watching in awe as the jewel began to glow a vivid golden hue. Brighter and brighter it radiated as the sea began to shift and swirl around the Alpha, knocking Castiel back even further. The once calm waters became a frenzied whirlpool around his mate, swallowing him in an Aurelian Vortex.

“Save him, save him, save him,” the Siren chanted as he watched frozen, unable to move, held in place by forces of the pearl’s magic. Praying that when it was all said and done that his Alpha would be alive, and would not hate him for what he had done.

A large pulse of magic rippled through the waters and Castiel shuddered at the sheer strength of it, never having felt anything like it in his life. After it passed the Siren’s eyes snapped back to the vortex, watching as the bright glow dulled, and the waters started to slow around his mate, gradually revealing him. Castiel’s over-riding thought was for the Alpha to be well. He just had to be, if anything happened to his mate he’d never be able to forgive himself. 

The Siren drew in a sharp breath as he took in the sight of his Alpha. The man’s skin was no longer pale, nor his lips blue, and even though he was still clearly unconscious Castiel could see the stable rise and fall from his chest. He was sure his mate’s heartbeat was just as strong. There was one thing in particular though, that the Omega couldn’t draw his gaze from, the long firm emerald tail, where legs had been only mere minutes ago. 

In the name of Queen Salacia! What had he done?

**Notes for the Chapter:**

> [ _**Graphics Masterpost created by ZephyrChrysalis here!**_ ](https://archiveofourown.org/works/15728604/chapters/36566784)
> 
> Oh and the song in this chapter is Siren by Red Delicious. I did change the word sailor to Alpha to fit better but the song is amazing if you have never heard it give it a listen.


	3. Chapter 3

**Notes for the Chapter:**

> Big thanks to Ani-make-me-girl for beta’ing this chapter, and zephyrchrysalis for Alpha reading and providing art.
> 
> Enjoy!

  


  


**“The meeting of two**

****lonely souls is the****

******meeting of the dark sea**** **

********with the moonlight.”**** ** **

********Mehmet Murat İldan**** ** **

******  
** ** **

********** **

  


Castiel swam back and forth across the expanse of the cave. His eyes never left the unconscious Alpha that now lay in a warm soft sand bed the Omega had created for him. Castiel wanted him to be as comfortable as possible while he slept off the after effects of the spell, and almost drowning. A pang of guilt jolted the Siren’s heart as he thought about how close he came to losing his mate, and how it had been his fault.

Had he done right by bringing him here? 

Castiel sighed as he continued his nervous swimming. 

Should he have taken him to Aunt Rowena instead? 

Castiel shook his head.

No, here was good. It would give him a chance to talk to his mate first, for them to get to know one another, and then they could decide the next step together.

If only his Alpha would just wake up.

The Siren continued his anxious flitting and deep thinking, only being drawn back to the present when he heard a low moan come from the sand bed. His eyes widened when he noticed movement, the man was coming around. Castiel quickly swam over and perched his face above the Alpha’s, waiting. 

Bleary green eyes slowly blinked open and met his.

“Hello,” Castiel greeted in a low timbre. 

The man screamed, clearly startled by the Siren looming over him. “Who the hell are you?” The Alpha barked as he pushed up on his elbows. “Where the hell am I?”

“My name is Castiel,” the Siren answered as he slowly moved back, giving his mate some space. “And you are in the caves close to your home.”

“Caves?” The Alpha looked around frantically, his eyes widening when a moon jellyfish swam by him. “I’m underwater!” he screeched. “How, what, how?” The man was hyperventilating now, he was scared, and Castiel itched to reach out and comfort him. 

“Am I dead! Did I drown?” He met Castiel’s eyes, his green ones full of horror, “Is this Heaven? Hell?”

“Calm down,” the Siren whispered as he cautiously inched closer, the need to comfort outweighing the need to give the man space. “You are not dead, I assure you.”

“Then what the hell is goi-” the sentence died on the Alpha’s tongue as he caught sight of Castiel’s tail swishing back and forth. “Stay back!” He shouted as his expression contorted into a look of pure dread. “What the hell are you?” 

Castiel flinched at his mate’s tone. 

His Alpha was afraid of him.

His true mate would never accept him for what he was.

“I promise,” Castiel held up his hands in a placating manner, “I would _never_ hurt you.”

“Yeah, right,” the Alpha scoffed. “Like I’m going to believe anything you say.” He sat up to get further away from the creature, but his movements were clumsy, it felt as if his legs were bound. The Alpha’s eyes trailed down his body and he let out a blood curdling scream when his gaze met his bottom half. 

“My legs!” the man screeched. “Where the hell are my legs?” He glared at Castiel as he clutched at his tail hoping to feel his legs hidden within it. “What did you do to me!”

Castiel’s heart was shattering, his mate likely thought he was a monster. Emotions getting the better of him the Siren yelled back, “I did the only thing I knew to save you!” 

The Omega wrapped his arms around himself as continued, his voice trembling as much as his body. “You were drowning, and I couldn’t let that happen.” He glanced up briefly meeting the Alpha’s eyes before he looked away, “I didn’t know the side effects would make you like me.”

They both fell quiet, lost in their own thoughts about the circumstances unfolding around them. After a few minutes of the deafening silence the Alpha couldn’t take it anymore, he blew out a deep breath and spoke.

“Dean Winchester.”

“What?” Castiel asked as he chanced a look at his mate.

“My name is Dean Winchester.” The Alpha shifted in the sand bed. “What are you, Ca, Cast, Casteel.”

“It’s Castiel,” he corrected gently as he flicked his fin in the sand, watching as the Alpha warily followed its movement. “I’m an Omega Merman, youngest son of King Triton.” He licked his lips and then whispered, “And as all other Omega Merfolk, I am also a Siren.”

“Omega Merman, son of a king, so that makes you a prince, huh?” Dean shook his head and snorted despite the situation. “Never met royalty before.”

“I’m no different than any of the other Merfolk,” Castiel shrugged as he watched a small angelfish flit by his face. “My mother taught me that even though we are royalty we are no better than anyone else.”

“That’s a good lesson,” Dean affirmed and Castiel nodded his agreement. 

The Alpha started picking at one of the green scales on his tail and Castiel watched as a look of curiosity spread across his mate’s face. Dean traced a few more scales with his fingertips before he cleared his throat, looking away from his tail and to the Siren. “Now that I’m not totally freaking out, Cas, do you think you can explain how I ended up,” Dean motioned to the lower half of his body, “like this.”

“Cas?” the Omega furrowed his brows and tilted his head to the side, contemplating.

“Nickname,” Dean explained. “Castiel is a mouthful man, Cas rolls of the tongue much easier.”

“I see,” Castiel hummed, his lips pursed. “I rather like it. You can continue to call me Cas.”

“Okay,” Dean huffed a small laugh. “Now that that's settled,” he motioned to his tail again. “How’d this happen?”

“Because of a wish,” Castiel mumbled, his fingers digging into the sand at his side, anything to keep them busy, to keep them from touching his mate like he so desperately wanted.

“A wish?” Dean repeated as he leaned forward and looked the Merman in his eyes. “Not really following. I’m gonna need you to start at the beginning.”

The Omega clutched at the sand nervously, this was the part he was dreading, telling Dean he was the reason he was here, like this, that he was the reason the Alpha almost drowned in the first place. But Castiel wouldn’t lie to him. Dean deserved to know the truth, even if it meant he would never forgive or accept Castiel as his true mate. 

“You remember how I told you I’m also a Siren?” Castiel waited until the Alpha nodded before continuing. “Do you know what Sirens do?”

“I read a story once when I was a child about a Siren and a sailor, but I can’t quite remember how it went.” Dean furrowed his brows in deep thought, trying to recall the tale from the old lore book his uncle had given him.

“Oh, Gods,” the Alpha gasped when pictures from the story and it’s grizzly ending flooded his mind. Those of a beautiful male Siren perched on the rocks singing to a young sailor who was completely under his thrall. And how that Siren watched as the young sailor’s ship crashed into those very rocks and the sea claimed his life.

“You!” Dean pointed at Castiel. The Alpha’s eyes widened when the storybook pictures in his head morphed into a hazy flash of himself stripping naked and wading out into the sea following the harmonious tone and the open arms of the beautiful Merman sitting across from him. “You tried to kill me!”

“I’m sorry, I’m so so sorry.” Castiel looked at Dean with pleading eyes, praying his mate could see how remorseful he really was as he continued to explain. “It’s the way of the Siren, it’s our nature. Once we reach our thirtieth year it’s time for our Rite of Passage, it’s time for us to start singing our death song and luring Alphas to the sea. You were to be my first.” The Omega’s shoulders slumped sorrowfully. “I know hearing this doesn’t make you feel any better, but, I just want you to understand. I _need_ you too understand.”

“I don’t get it then,” Dean shook his head as he scooted back a few inches so he could lean against a large rock. “You say it’s your way, your nature, and you had me where you wanted me, why go through the trouble of saving my life?”

“As you were going under the wind changed its course, and a distinct scent wafted by my nose.” A small smile tugged at Castiel’s lips. “It was a scent like no other, it was _perfect_ ”

“What was it?” Dean asked, grimacing when a sharp edge of the rock dug into his lower back.

“You,” Castiel whispered as he looked at Dean through his dark lashes. “Earthy island driftwood and warm amber, like love and comfort, like home and _true mate_.” The Omega leaned forward slowly and gazed into Dean’s eyes. “You are my Alpha, I couldn’t let my mate die.”

“What, woah, what?” Dean’s eyes widened as he let out a nervous laugh. “Cas, we aren’t even the same species, how the hell can we be true mates?”

“I don’t know,” Castiel shrugged as he scooted a little closer to Dean, “but we are.” The Siren’s brows dipped in consternation, “Can’t you tell from my scent?”

“I’ve been uh,” Dean sighed and scrubbed his hands down his face, “been a bit preoccupied freaking the fuck out to do any scenting. So no, honestly I haven’t a clue what you even smell like.”

“Would you like to?” Castiel queried as he gingerly closed the gap between them, sitting down beside Dean and leaning against the rock.

“I-I,” Dean stuttered as he looked over at the Merman. He was truly beautiful. His dark hair and his ethereal blue eyes were even better than his dream. Dean’s gaze roamed over the Merman’s face, his breath hitched at the strong jawline and he wondered how those supple lips would feel under his. As he surveyed his ‘mate’ further he had to admit that the man was enticing. His chest was smooth and defined without looking hard or bulky. Dean wanted to run his hands across it, but at the same time, he wasn’t sure about this whole true mates thing especially when he looked at the Merman’s tail. It was intimidating. But with its iridescent obsidian sheen with shades of blue he had never seen before it was also absolutely stunning. 

“Yes,” Dean whispered. Deciding he would do it if only to prove to himself that this Omega was not his true mate, even if Castiel did have the same dark hair and blue eyes from his dreams.

“Alright,” Castiel hummed as he tilted his head to the side, bearing his throat to the Alpha, giving him his full permission to scent him.

Dean exhaled shakily before slowly leaning in and pressing his nose against Castiel’s mating gland where his essence would be the strongest. He snuffled at the Omega’s neck, breathing in deep, and holding back a groan that threatened to spill past his lips.

Castiel smelled exotic, uniquely sweet like a freshly cracked coconut, mixed with a slight nutty aroma. It reminded Dean of hot summer days, and the scent of his skin after he slathered it with sunscreen. It was perfect, filled him with a sense of happiness and adoration, of home, but most of all it made his inner Alpha scream _true mate_.

“My Omega,” Dean rumbled on a breathy sigh as he fought the urge to lick a stripe up Castiel’s milky white flesh, or better yet suck and bite, show everyone this Omega was taken, was his. Dean took one final breath of his mate’s scent and moved back before he gave in to his inner Alpha. He met Castiel’s eyes and grinned, “You are mine.”

“Yes,” a smile broke out on the Omega’s face, matching that of his Alpha’s. “I am.”

“Okay, one thing at a time though,” Dean licked his lips and folded his hands in his lap, trying to ignore just how much his inner Alpha wanted to pull Castiel in his lap and mark his pretty unmarred throat. “We will come back to the whole figuring out how it's even possible we are true mates thing after you finish telling me about this wish, and how I became a-a Merman.”

“Right,” Castiel shook his head, clearing the fog from his brain at having his Alpha in such close proximity. “When I caught your scent and knew you were mine, I looked back out at the waters and you were gone, the current had dragged you under. I was frantic,” he shuddered, remembering the fear that had coursed through his veins. “I took a deep breath, dove from the rock, and started searching for you. When I found you, you were, your heartbeat was so weak. I-” Castiel’s breath hitched and he could feel tears welling up in his eyes at the mere thought of how close he had come to losing Dean. 

The Alpha reached over and placed his hand on Castiel’s giving it a comforting squeeze, assure his Omega he was still here, he was alive. “Go on,” Dean encouraged as he threaded their fingers together.

“I just knew I couldn’t let you die. So I used the necklace my mother gave me on her deathbed.” At the Alpha’s confused look Castiel brought the hand not holding Dean’s up to caress the pearl. “One single wish was contained in this black pearl, put there by my aunt as a gift for my mom. She never used it.” Castiel smiled as he let go of the pearl and let his hand fall back to his lap. “Said her life had been perfect, that she had no need. So she gave it to me and told me it was meant for something great and I’d know when the time came.” The Siren gazed into Dean’s eyes his smile growing, “And I did. When I knew I couldn’t get you to the surface in time I pressed my lips to yours and passed the Oxygen I took in before diving in after you, hoping it would be enough for you to hold on for just a while longer.”

“What happened next?” Dean asked completely enthralled by the Siren’s recounting of the events that led them here.

  


  


“I quickly removed my necklace and refastened it around your throat. Then I pressed my hand,” Castiel reached up again and placed his palm against the pearl, “here. And I said, please save him. I wish to save my mate.”

Castiel hand moved from the pearl, “I was so scared. The sea began to shift and swirl around you, it knocked me back and all I could do was watch and wait, pray to the Gods that you would live.” He cupped the Alpha’s cheek, “When the waters calmed and I saw the stable rise and fall from your chest, and I was sure your heartbeat was just as strong, I felt such a sense of relief that I hadn’t lost you.”

The Omega blew out a shaky breath and removed his hand from the Alpha’s cheek. “Then I saw your tail, and my first thoughts were selfish. I couldn’t draw my gaze away, it mesmerized me. Long and firm, a dazzling emerald color that almost rivals that of your stunning eyes. Then reality set in, and all I could think was that you were going to hate me for what I had done.” 

“I don’t though,” Dean whispered surprised at the truth of that statement. Despite what the Siren had done he held no ill will towards him. “I can’t fault you for your nature. Plus you're my true mate, you’re all I’ve ever wanted. If you hadn’t called me to the sea we may never have found each other.” He gently nuzzled at the side of his Omega’s throat, sighing when Castiel’s sweet scent surrounded him. “And, you used your one wish to save me.” The Alpha placed a gentle kiss to the Siren’s pulse point. “So how could I hate you?”

“It would make things easier if you did.” Castiel muttered, his chest aching at the thought. But really, what was the likelihood of Dean giving up his life and staying here with him, if there was a way Rowena could reverse the magic to give him his legs back. And knowing his aunt, he was sure that was not out of the realm of possibility for her. “Easier for when you leave me.”

“Cas, what are you talking about?” Dean pulled back, his brows furrowed as he stared deep into his mate’s sad eyes. The Alpha reached up and ran his fingers back through his Omega’s hair. “What do you mean leave you?” 

“I mean how can we be together?” Castiel asked as he leaned into his mate’s affections. “We’re from two different worlds. You have a life up there.” The Omega nodded skyward, “On land. Where I can’t follow.”

“Hey,” Dean pulled back and cupped his Omega’s face gently. “We’ll figure it out, okay?” The Alpha brushed his thumbs along his mate’s jawline. “Now that I’ve found you, I’m not letting you go. I promise you that.”

“I believe you,” Castiel whispered, seeing nothing but truth in his mate’s eyes and bright aura. 

The Siren glanced up through a hole in the roof of the cave and let out a low hum. “It will be morning soon. When the sun begins to rise we will go visit my Aunt Rowena, she will be able to tell us more about the spell the pearl put on you.”

“Sounds like a plan. Hey, Cas?” Dean wrapped his arm around his mate’s shoulder his inner Alpha preening when Castiel snuggled closer. “Since we have some time to kill can I ask you a question?” When he felt his mate nod against his chest he continued, “How can Merfolk see so well at night, in the dark of the sea?”

“We have nocturnal vision. It allows us to see pretty much the same in the night as the day.” The Omega nuzzled at his mate’s strong chest humming in contentment before carrying on with his explanation. “And the moon jellies,” Castiel pointed at a blue and green one illuminating over their heads. “They are also a useful source of light.”

  


  


“Yeah,” Dean snorted as he watched them glide along. “Like little moving light bulbs.”

“Mm-hm,” Castiel nodded with a small smirk aimed up at his mate. “Roaming electricity, way better than what you Landfolk have.”

“Funny,” Dean snorted as he poked his mate in the side, grinning when Castiel tried to wiggle away. “Ticklish?” Dean teased as he matched his mate’s smile and did it again and again, loving the breathy giggles it drew from his Omega. 

Dean continued his relentless tickling until Castiel was begging. “No more, no more! Please!” The Omega choked out around laughter. “Please, _Alpha_.”

“Since you asked so nicely,” Dean cooed with one final poke earning him a glare from Castiel. The Alpha snorted and placed his hands on his lap. 

Dean’s eyes widened as he just remembered something, something he was surprised he hadn’t thought about before now. “Oh, shit! Oh, my Gods!” Dean wailed as he glared down at his lap. “My dick! Where’s my cock, Cas?” His gaze snapped over to his mate, “I still have one right?!”

“Yes,” Castiel nodded trying his best to stifle a laugh. “You still have a penis, Dean.”

“Tell me where it is!” Dean demanded as he stared down at his crotch, as if willing his dick to appear.

“Behind your sheath.” At his mate’s utterly horrified and confused look Castiel reached over and placed his hand on Dean’s groin and rubbed gently. “Right here, Dean.”

“Oh,” the Alpha grunted when he felt the familiar stirring of arousal low in his gut, and a twitch from beneath his scales. “O-okay,” Dean let out a breathy sigh as he unconsciously bucked up into his Omega’s touch.

“See? You feel that?” Dean nodded slowly and Castiel smirked as the heady scent of lust rolled off his mate, filling the Siren’s nostrils. Castiel removed his hand before things got too heated too fast. 

The Omega cleared his throat and began to explain, “We have sheaths, front and back, the scales part when needed, or with sexual stimulation.”

“Alright,” Dean sighed in relief, his cock still slightly excited from his mate’s touch. He shifted and tried to will his body to calm. They weren’t ready for that, not yet. Figuring a change of topic would help, Dean turned to Castiel. “I have another question.”

“You can ask me anything,” Castiel replied, a little breathless from touching his mate in such a way. He laid his head back down on Dean’s shoulder and waited.

“How does breathing underwater work?” The Alpha took in a deep breath and released it. “It feels almost the same. A little heavier, maybe?” He looked down at Castiel, “Does that make sense?”

“Yes,” Cas nodded. “It feels heavier because of the water you are taking in.” He sat up and faced his mate. “As for how breathing underwater works, we have gills.” 

“Really? Where!” Dean exclaimed as he brought his hands up to his throat and started to poke around.

“You won't be able to feel them,” Castiel shook his head laughing. “We have internal gills. They are located around where you were touching just on the inside of our throat.”

“Oh, gotcha.” Dean lowered his hands, wanting skin contact with his mate again, he wrapped an arm around Castiel’s shoulder as he waited for him to continue.

“So when you breathe, you take in oxygen rich water, it passes over, around, and then through the gills. As the water passes through the gills, the oxygen in the water is separated and goes into your blood, and then to your heart.” Castiel thinks the perplexed look on his mates face is adorable and he can’t help but to ask. “Make sense?”

“Yeah,” Dean nodded briskly, “oh yeah, total sense.” The Alpha rolled his eyes when the smirk spreading across Castiel’s lips made him realize his mate was poking fun at him. 

“Smartass,” Dean mumbled and the Omega’s smirk grew. The Alpha cleared his throat, “Well I mean not _total_ sense but I’m following along rather well, I think.” Dean’s brows dipped in thought as he ran through all the new information Castiel had just given him. “What happens to the water after the gills separate the oxygen from it?”

“The water then gets absorbed in our skin and that allows us to be able to stay on the surface longer without drying out.” Castiel gave him a bright smile, “Merfolk love to sun on the rocks.” 

“Aren’t you guys worried about being seen?” Dean asked as he dug his tail in the sand smiling when the grains ticked his fin the same way it had when he had feet. “I mean, isn’t it dangerous?”

“It can be,” Castiel whispered as he drew his tail closer to his body and wrapped his arms around it.

The smell of distressed mate filled Dean’s nostrils and the smile from his face fell. He wrapped both arms around his Omega and nuzzled at his jaw. Castiel let out a shuddering breath and leaned into his mate. He clearly wasn’t ready to talk about whatever caused that reaction and Dean wasn’t about to push. So he placed a kiss to Castiel’s throat and held him tightly, hoping to convey that whenever his Omega was ready to talk he would be there to listen.

They stayed like that in each other’s arms until Castiel’s distressed scent melted into one of tranquility. Dean’s fingers traced random patterns on his mate’s arm, they took turns nuzzling and scent marking each other. The sea serene around them, as a variety of creatures swam or scuttled past. When light shone through the hole in the top of the cave they knew dawn had broken.

Castiel let out a soft sigh and looked up at Dean, “It’s time to go.”

“Okay,” Dean nodded, but when Castiel started to move the Alpha held him tighter. “Wait,” he whispered and he cupped the Omega’s jaw. “Can I kiss you first?”

“Yes,” Castiel whispered as he stared deep into emerald eyes. “I would really like if you did.”

“Good,” Dean smiled as he pressed his lips to Castiel’s, swallowing the Omega’s breathy sigh. His inner Alpha howled when his mate’s melted in his hold like warm butter. Dean deepened the kiss, slipping his tongue into Castiel’s mouth when he opened willingly for him. Their tongues tangled and danced together, moved perfectly in unison in a way only true mates can. They kissed and traded soft caresses until their lips tingled, until Dean reluctantly moved back when his inner Alpha began to howl for _more_. He rested his forehead against his Castiel’s as he muttered. “That was perfect.”

“I have to agree,” Castiel mumbled as he pressed another chaste kiss to his Alpha’s lips. The Omega let out a deep sigh, and pooched his bottom lip out in a pout. “But we really must get going, are you ready?”

“To meet a Sea Witch?” Dean nipped his mate’s bottom lip. “Not something one gets to do every day—should be interesting.”

“Don’t let her hear you call her a Sea Witch, she prefers Sea Enchantress.” Castiel smirked at his mate, “I’d hate for her to turn you into a crab because of a slip of the tongue.”

“She wouldn’t,” Dean gasped with wide eyes.

Castiel shrugged as his smirk grew, “You never know with Aunt Rowena.”

“Sea Enchantress it is then,” Dean nodded and motioned with his hand. “Lead the way, Cas.”

**Notes for the Chapter:**

> Hope you enjoyed the chapter!
> 
> [ _**Graphics Masterpost created by ZephyrChrysalis here!**_ ](https://archiveofourown.org/works/15728604/chapters/36566784)


	4. Chapter 4

**Notes for the Chapter:**

> Big thanks to Ani-make-me-girl for beta’ing this chapter, and zephyrchrysalis for Alpha reading and providing art.
> 
> This chapter is a long one!
> 
> Enjoy! :)

  


**“The sea, once it casts its spell,**

**holds one in its net of wonder**

**forever.”**

**Jacques Yves Cousteau**

  


  


“This swimming with a tail thing is hard,” Dean grumbled as he watched Castiel glide fluidly in front of him.

The Siren spun around and watched Dean’s movements. “You’re doing it wrong.” He grinned as he swam over beside his Alpha. “Your fluke is responsible for moving you forward. You don’t wiggle your whole tail.”

“My what now?” Dean asked with a furrowed brow, grunting as he barely treaded water.

“Fluke,” Castiel nodded to his tailfin. “You move it up and down, it catches water and propels you forward. Watch me.” Dean observed closely as Castiel’s fin undulated and he gracefully sliced through the water. “You try,” the Omega called over his shoulder.

Dean bit his bottom lip and mimicked Castiel’s movement, smiling when he flitted up beside Castiel. “I did it!” The Alpha crowed as flicked his fluke faster, passing his mate.

“See, already a pro at it.” Castiel grinned as he watched his Alpha swim with confidence, as if he’d been doing it his entire life.

After a few minutes of following closely behind his mate, admiring how his Alpha’s strong tail rippled as he moved, the Omega sped up until he was at Dean’s side. “We’ll be at Aunt Rowena’s soon.” Castiel said as he grabbed Dean’s arm and pulled him deeper, so they wouldn’t disturb a school of yellowtail fusiliers swimming above them. “She lives in the outer limits of Atlantis, so it should be easy getting there without being seen.”

“Atlantis!” Dean’s eyes widened, his gaze snapped over to his mate. “As in the lost City of Atlantis?”

“Not lost,” Castiel smirked at his Alpha. “Just hidden.”

“Well, I’ll be damned,” Dean murmured as Castiel reached over and took his mate’s hand, leading them toward the city. 

As they dipped and swam through a trench, Dean gripped his Omega’s hand tighter when a large stingray swam alongside them. “Don’t worry,” Castiel whispered as he reached out and ran his hand along the ray’s pectoral fin. “He won’t hurt you. Go on,” the Omega nodded towards the aquatic creature. Dean tentatively stretched out his arm and ran his fingers along where Castiel had touched, grinning over at his mate as he did so. When the Alpha withdrew his fingers the ray darted past them, just as the trench opened wider, revealing the whole of Atlantis. Dean’s breath caught at the sight of the lost city. It was wondrous to behold. The Alpha had never seen anything like it in his entire life. 

The word breathtaking just did not do it justice. Atlantis was a true homage to the soaring Greek architecture. Doric columns rose as if to break the barrier between the sea and the heavens. The colonnade of Gods and Goddesses looked down on him and he felt smaller than he ever had before. And he was an Alpha, nothing ever made him feel small. 

These Gods and Goddesses were the keepers and reminders of a rich history, lost too soon. And while they protected their history, they had their own guardians. Patience and Fortitude, the two abalone crystal lions perched on either side of the luminously pale blue of the Larimar stone entrance gate barring the way of any interloper.

  


  


Through the Gates of Atlantis, lay a city of magnificent stone dwellings. There were homes in a variety of sizes and jewel like colors that sparkled in the seas reflected light. A large silver temple that Dean assumed was a place of worship, or for the citizens to gather, was in the midst of a cluster of homes. Numerous gardens filled with a variety of colorful sea plants surrounded the temple. 

Once past the temple the passage opened up to another colonnade that rose up onto a small but majestic seamount that was home to an ornately carved castle of white and grey coral and abalone. The passageway to the castle was lined in gold and glimmered with the reflection of the jeweled prisms that stood atop the castle’s turrets. 

As Dean studied the castle more intensely, he could see that it was comprised of nine tall round towers. They formed almost a perfect circle. Each tower was connected by thickly carved walls of black obsidian stone. Elegantly etched windows were scattered generously around the walls in perfect symmetry, along with overhanging crenellations for archers and artillery. The massive columns and cylindrical towers loomed over all the other structures around it. 

“Wow,” Dean whispered in awe as he glanced over to Castiel. “It’s astonishing. I’ve never in my life seen anything so amazing.”

“It’s home.” Castiel replied back using the same reverent whisper as his mate while giving Dean’s hand a gentle squeeze. “Come on, we best get to Aunt Rowena’s before the sun fully rises and Merfolk start milling about.” He glanced over at Dean, “They’ll surely ask questions when they notice an outsider.”

“Then let's get a move on,” Dean flicked his tail nervously as he watched his mate scan the inside of the city, looking for any early risers. When the Siren deemed it safe, he gripped Dean’s hand tighter and led him to the entrance. 

Out of the corner of the Alpha’s eye something shiny caught his attention. He looked to his left and noticed a large grotto, with sparkling gems blended into the rocks. “What’s that over there?” Dean asked as he nodded in the direction of the cavern.

“That’s the Crystal Cave,” Castiel replied after a quick glance at the grotto. “I use to play there with friends, when I was a youngling.”

“Pretty,” Dean mumbled as he cast one last look at the cave, before his gaze fell back to gateway in front of him.

As they passed through the gates the Alpha regarded the lions warily. Though made of abalone crystal they looked so real, as if they could jump from their perch at any moment and maul him for being an outsider. Dean let out a breath he hadn’t even realized he was holding when they had safely passed through without any casualties.

“Just over here,” Castiel nodded to one of the larger stone dwellings. This home had a gleam to it that reminded Dean of the inside of a large conch shells. The colors ran from the creamy peaches and taupes, to a deeper nutty brown. The bright red coral that dotted the surrounding gardens were stunning and provided a wonderful contrast to the white coral that lined the pathway to the shimmering front door. 

Dean glanced around at the other surrounding dwellings. Each was a different stone or combination and all were equally beautiful. “Everything is so stunning here.”

“I’m glad you think so.” Castiel grinned over at Dean as he gripped his Alpha’s hand tighter, and flicked his fluke faster, propelling them towards their destination at a urgent pace. When they reached the door Castiel rapped on it hastily, “Aunt Rowena,” he hissed, “It’s Castiel. It’s important. Please, open up.”

“I'm coming, I’m coming, hold your seahorses, Castiel.” Came the muffled response from the other side of the door.

“Well move faster,” the Omega called back as he knocked on the door again.

“This better be damn important for disturbing me this early,” Rowena griped as she swung the door open and eyed the pair on the other side. “Oh,” she gasped as her gaze darted from Castiel’s necklace around the Alpha’s throat to their joined hand. “This looks to be _very_ important. I forgive you for disrupting my beauty sleep.” A wicked smirk spread across her ruby red lips as she glided from the doorway, “Come on in and tell Auntie Rowena all about it.” 

As Castiel shut the door behind them Dean took Rowena’s hand and placed a kiss to it as he gave her a roguish grin. “You, Dear Lady, don’t need any more beauty sleep.” His grinned broadened, “surely, you don’t want to put everyone else to shame, now, do you?”

“Sweet boy,” Rowena cooed as she patted his cheek and shook her head, her fiery crimson hair flowed around her and was complemented by the variety of reds in her shelled corset. As she placed her hands on her hips Dean’s noticed her delicate tail was the same vibrant shade of crimson as her hair, except for her fluke. As her tailed tapered off to her fins the red blended to a beautiful iridescent pale apricot that painted the tips. She smirked at her nephew, “Where did you find this charming land Alpha?”

“What?” Castiel’s eyes widened as he stared at his Aunt. “How did you know?”

“Really, Castiel,” Rowena quirked a brow. “He’s wearing your necklace, which is now void of it’s one wish. And since I was the maker of that necklace, I can see the spell that was used to grant your wish. Sit down, the both of you,” she motioned to a rectangular green and black malachite table with matching boulder shaped seats. “I’m going to need coffee first, before you explain how the hell this,” she pointed at Dean, “happened. Would you boys like some as well?”

“Yes, please,” Castiel replied as he guided Dean towards the table.

“Sure,” Dean grunted as Castiel tugged his hand, pulling the Alpha down to where he was sitting on the seat beside his Omega. “Wait, what?” Dean’s eyes snapped over to Rowena where she was preparing coffee in an honest to Gods coffee maker. “How?” He pointed at the machine, “How the hell are you using that underwater, and how does the coffee not just float away when you pour it?”

“Clueless land Alpha,” Rowena sighed as she place the carafe and three mugs onto a tray before daintily gliding to them. She placed the mugs on the table, picked up the carafe, observing the look on the Alpha’s face as she tipped it forward and the coffee flowed into the cup. Dean looked up at her with wide eyes filled with astonishment and she grinned at him. “Magic my dear, that’s how.” Rowena replied as she slid the full mug towards him.

“Awesome,” Dean beamed as he wrapped his hands around the mug feeling the warmth against his palms, watching Rowena as she filled the other two cups.

“Would either of you like sugar or creamer?” Rowena asked as she nodded towards her refrigerator. 

“You have a fridge too!” Dean’s brows furrowed as he glanced up at her. “How’d you manage to get all this stuff?”

“Like I said, Dear Boy, magic.” She called over her shoulder as she swam to the refrigerator to retrieve the creamer and the bowl of sugar on the countertop. When she joined them back at the table and the Alpha still had the same look of curiosity on his face she began to explain. “The Atlantis library has vast knowledge of land living. The appliances you use in your everyday lives, the recipes for foods you make. The things we thought could improve our way of living we studied, and those of us blessed with magics replicated them. Spelled ovens to cook with, refrigerators to keep chilled and frozen those items that require it. Enchanted cups that hold liquid, and plates and cookware that keeps food from getting waterlogged.” Rowena gave him a small smirk as she added creamer to her coffee. “Did you think we just lived off of raw fish and seaweed?”

“I don’t know, maybe,” Dean grumbled as he took a sip of his coffee. “Cut me some slack, I’m new to all this.”

“And your taking everything in wonderfully,” Castiel whispered as he reached over and placed his hand on top his mate’s. 

“Thanks,” Dean replied as he gave Castiel a small smile before asking, “so if not all of you guys are skilled in magic does that mean that only certain Merfolk have modern appliances, and the ability to have foods other than,” he snorted as he grinned impishly at Rowena, “raw fish and seaweed?”

“No,” Castiel shook his head as he spooned some sugar into his coffee. “Those who are not versed in the arts can barter with those like Aunt Rowena to make them the appliances they want. And as far as foods go, we have a market operated by an Enchanter and Enchantress mated couple who trade with Merfolk who don’t have the abilities to conjure their own foods to cook. They also have recipe books for those who don’t know how to properly prepare their meals.”

“Wow, I’m impressed,” Dean hummed as he took another swig of his coffee. “So barter, huh? I’m guessing you guys have no need for cash, so what do Merfolk trade in?”

“Different things. I for example,” Rowena reached up and trailed her fingers across the diamond choker around her, “take jewels as payment.”

Dean opened his mouth to speak but was cut off by the loud rumbling of his stomach. “Sorry,” he mumbled as he looked from Castiel to Rowena, grinning sheepishly. “Been a while since I last ate.”

“I can tell,” Rowena shifted off her seat and flitted over to the counter beside the stove. She picked up an elegant snow white china plate, decorated in sprays of dark pink roses, with a scallop-edged domed top. She swam back to the table and placed it in the center before removing the top, revealing six large scrumptious looking muffins. “Well go on, dearie, eat.” Rowena nodded to the muffins before looking at the Alpha who was eying them with caution. “I guarantee they are just as good as the ones you can get on land,” after a pause she added with a smirk, “probably better.”

Dean tentatively reached out and took one in his hand. He gave it a gentle squeeze. It felt firm, slightly springy, not a drop of water was seeping into it making it mushy. The Alpha brought it to his mouth and took a huge bite, groaning as the flavor of chocolate and cinnamon burst across his taste buds.

“This is amazing,” Dean mumbled around a mouthful of the sweet treat, bits of the muffin spraying from his mouth.

“Such a refined Alpha,” Rowena mumbled as she poured herself another cup of coffee. “Now that I have caffeine in my system, and we got some food in him,” she pointed to Dean, before turning her attention to her nephew. “It’s time to tell me why this land Alpha is here with you, Castiel. Why you used your wish on him, and why you two seem awfully cozy with each other.” 

“He’s my true mate,” Castiel mumbled as he reached for one of the muffins.

“I beg your pardon?” Rowena asked, sputtering the drink of coffee she’d just taken.

“He is my true mate,” Castiel repeated slowly as he met his aunt’s eyes and sat up straighter.

“A land Alpha?” She glanced over at Dean then back to Castiel, shock clear on her features. “A land Alpha is your true mate?”

Castiel opened his mouth to answer but Dean beat him to it. “Trust me, I am just as surprised as you.” The Alpha popped the last piece of muffin in his mouth, chewing and swallowing before continuing, “But somehow we are true mates.” He grinned over at his Omega who was picking at his muffin. “The moment I scented Cas I just _knew_ he was mine. I don’t know how it’s possible, but we belong to each other. I feel it deep in my bones.”

Rowena blew out a deep breath as she whispered in awe, “Well, I’ll be damned. How,” she licked her lips and stared at the pair, “how’d you two find each other.”

Dean grinned over at Castiel, “Why don’t you answer that one, Sweetheat.” He winked at his mate as he snagged another muffin.

“Umm,” Castiel sighed as he met his aunt’s eyes. “Dean is the Alpha I had chosen for my Rite.”

“You are kidding me,” Rowena giggled around the lip of her coffee mug. “You tried to _kill_ your true mate.”

Dean snorted and Castiel shot him a glare before looking back to Rowena and continuing. “Well, yes, but I didn’t.”

“Oh this is too good. I haven’t heard anything this entertaining in ages.” Rowena exclaimed as she grabbed a muffin and took a bite. “Go on, Castiel,” she motioned with her free hand.

“I sang for Dean and he followed my voice, followed it out into the deep of the sea. Before he went under the wind changed its course and I caught his scent. In that moment I knew,” Castiel whispered as he twisted the chocolate chip muffin in his hands. “I dove in after him and when I found him I knew I couldn’t get him to the surface in time. So I did the only thing I knew to save him.” He dauntlessly met his aunt’s eyes. “And I don’t regret it, I’d gladly do it again.”

“Well,” Rowena shook her head. “I’ll say it again, _I’ll be damned_.”

The trio fell silent, the only sounds in the room was the clink of mugs hitting the table as they drank, and gentle chewing as muffins were consumed. When Rowena polished off her coffee and the last bite of her muffin she glanced over at Dean with her brows furrowed. “Dean,” she waited until she had the Alpha’s attention before pressing forward, “by any chance have you been having strange repetitive dreams for a little over a year now, did your inner Alpha feel drawn to this place?”

“How,” Dean shook his head and cleared his throat. “How’d you know about that?”

Rowena ignored his question in favor of turning to her nephew and asking one of her own. “And you, Castiel, did you feel an intense urge to not want, but _need_ to sing to Dean before last night?”

“I…” Castiel trailed off and looked over at his mate. “Yes, and it was so _strong_.”

“Bloody hell it worked!” Rowena exclaimed as she grinned at the pair. “It actually worked.”

“What are you talking about?” Dean inquired as he wrapped his arms around his mate, his inner Alpha needing to touch his Omega.

“Weeelllll,” Rowena drawled as her grinned turned a might sheepish. “I may have played a wee part in those dreams starting, Dean. _And_ ,” she turned to her nephew, “the reason that you, Castiel, were so drawn to Dean before the night you actually sang to him.”

“May have,” Cas deadpanned as he quirked a brow at his aunt.

“Alright I did,” she let out a deep sigh and began to fiddle with her coffee cup. “I knew how important it was for you to find your true mate so I cast a spell.”

“Why didn’t you tell me,” Castiel whispered as met his aunt’s eyes.

“I didn’t want to get your hopes up,” she admitted with a small shrug. “True mate magic can be fickle. The Gods don’t tend to like us meddling with fate. So ninety-nine percent of the time it doesn’t work.” She let out a chuckle as she smirked, “But if I’d known your mate was a land Alpha, and that you would bloody well try to sing him to an early grave, I would have.”

“Yeah,” Dean let out a bark of laughter. “A little warning would have been nice. Being almost murdered by your true mate,” he ticked his head, “not exactly a romantic meet story to tell the family.”

Castiel let out a small chuckle of his own at his mate’s response before rising up, leaning over the table, and wrapping his aunt into a hug. “Thank you,” he whispered into her ear before pressing a kiss to her cheek and sitting back down. 

“You’re welcome,” Rowena reached over and patted Castiel’s hand. “All I’ve ever wanted is for you to be truly happy, Castiel, for you to be with the one person meant for you.”

“I am happy,” Castiel whispered as he looked over at his mate who was watching the exchange intently. But,” he let out a deep sigh, “I’m curious about the spell the pearl put on Dean. Can you tell us about it?”

“Of course,” Rowena rolled her eyes playfully, “it’s me you're talking about.” She propped her elbow on the table and rested her chin in her palm as she studied Dean closely. “Well, it read your heart’s desire, not only of saving your mate, but making it so the two of you could be together.”

“I-” Castiel swallowed the lump in his throat. “I did this to Dean.” He glanced over at his mate who had a look of profound confusion on his features. The Omega suddenly felt sick to his stomach. He’d taken the choice out of Dean’s hands. His selfishness had made this momentous decision for his Alpha. Dean has a life up on the surface and Castiel’s need to be with him had potentially taken that away. Dean had the right to make this life changing choice, and the Omega couldn’t live with himself if he didn’t try everything in his power to make that decision possible for him.

Castiel took a deep breath. He looked Rowena in her eyes with a look of pure determination as he asked the most difficult question, probably of his entire life. “Can it be reversed?”

Rowena nodded, looking completely taken back by her nephew’s question. She opened her mouth to speak but Dean beat her to it. 

“Castiel, wh-” the Alpha’s sentence was cut off by the sound of Rowena’s door being swung open.

“Hey, Aunt Ro, have you seen Cassie?” Gabriel called out as he swam into the room, pausing in his movement as he caught sight of the trio at the table. His eyes narrowed as they landed on the strange Alpha sitting far too close to Castiel. “Who the hell are you?” Gabriel barked out as he scented the air, his next words coming out in a growl, “And why the hell do you smell like my little brother?”

“Uh, well,” Dean held up his hands in a placating manner as he thought about how to answer. It was probably a bad idea to go with the truth. No way did he want to tell a pissed off big brother Alpha Merman that the reason he smelled like his little brother was because they spent a good portion of the night scent marking and nuzzling each other. And kissed, it had only been one kiss, but wow, it had been an amazing one. Oh, and let’s not forget the little bit of sheath rubbing, to prove to him he still had a cock. Dean’s brows furrowed, yeah the truth was _definitely_ a no go.

“Little help here, Cas.” Dean whispered to his mate.

Before Castiel had a chance to come to his mate’s aid, Gabriel sliced through the water and towards him with such speed Dean didn’t even have a chance to react. Gabriel gripped the other Alpha by the shoulders, hauled him up from his seat, and slammed him up against the stone wall a few feet behind where he’d been sitting only moments ago.

“Oh, Dear,” Rowena mumbled as her eyes widened and flickered to Castiel who had the same stunned expression on his face, then back to her other nephew who was currently choking the life out of Castiel’s mate.

“I’ll ask you one more time and I expect an answer,” Gabriel snarled in Dean’s face. “Why do you smell like Castiel?” Gabriel’s eyes dropped down to the necklace around the other Alpha’s throat that was cutting into his hand. His growl deepened when he recognized it. “And why are you wearing the necklace our mother gave him?”

“Look, man,” Dean wheezed and sputtered as he clawed at the Merman’s hands. “Loosen up, you’re choking the life out of me.”

“Fine by me,” Gabriel snapped as his fingers twitched against Dean’s abused skin.

Black spots began to dance across Dean’s field of vision before he heard a very pissed off Cas yell, “Get the fuck off of him right now!”

Suddenly Dean could breathe again. He doubled over gasping as he tried to catch his breath. When his head no longer felt fuzzy he straightened up and was met with the sight of his Omega aggressively slapping his older brother in the sides and stomach with his fluke.

“Ouch, damnit, Cassie,” Gabriel grumbled as he wrapped his arms around himself and tried to protect his body from the blows that just kept coming from one very pissed off Omega. “Shit, stop fin-slapping me! That really fuckin’ hurts!”

“You deserve it!” Castiel growled. “Treating me like I’m some helpless Omega, that needs saving by his Alpha big brother.”

“Gotta agree with him there.” Rowena added, watching in amazement as she poured herself another cup of coffee.

“Aunt Ro,” Gabriel grunted as Castiel landed another well placed slap to his abdomen.

“Well, you do,” she chastised. “Coming in here acting like an Alpha Cave Merman, didn’t even give them a chance to explain before attacking. You should be ashamed.” Rowena tsked and took a sip of her coffee before adding, “I know your mother raised you better than that, Gabriel.”

At the mention of their mother Castiel stopped his relentless attack. He was breathless and still a little tense, but the anger slowly bled from his features. 

Gabriel straightened up, a look of guilt on his face as he mumbled, “You’re right, Aunt Ro.” He met Castiel’s eyes before saying, “I’m sorry, brother.”

“For?” Castiel huffed.

Gabriel let out a long contrite sigh, “I apologize for treating you like some helpless Omega, that needs saving by his Alpha big brother.” He grumbled and rubbed his sides, “With a fin-slap like that you can take care of yourself for sure.”

“I accept your apology, but,” Castiel crossed his arms over his chest and quirked a brow. “I’m not the only one _you_ need to apologize to.” He nodded towards his mate, “Now, you tell Dean you're sorry for acting like an overprotective hot-headed asshole.”

“Okay,” Gabriel pouted like a scolded youngling as he moved forward until he was in front of the other Alpha. “Okay, so as you now know, I’m Castiel’s older brother, Gabriel. And, I’m sorry, Dean,” he held out his hand. “No hard feelings?”

Dean eyed the hand warily for a moment before nodding and taking it in his own. “Yeah, okay. No hard feelings. I’m a big brother too, so I understand where you're coming from.”

“You are?” Castiel whispered as he caught Dean’s eyes. The guilty feeling in the pit of his stomach returning tenfold at the knowledge Dean had a little brother waiting for him on land.

“Yeah,” Dean smiled and bobbed his head. “And since I’ve had the pleasure of meeting your brother,” Dean snorted as he glanced over at Gabriel, who was still watching him with a keen expression. “I’ll tell you all about Sammy.”

“Later,” Gabriel held up his hands halting any further conversation of families. “First could someone please explain to me what the fuck is going on here?”

“Language,” Rowena chastised as she narrowed her eyes at her eldest nephew. “And if you are willing to behave, I’m sure Dean and Castiel will answer any questions you have for them.”

“Okay,” Gabriel flitted over and plopped down beside Rowena as Castiel and Dean took their previous seats. “What’s going on?” Gabriel blurted out once more as soon as everyone was settled.

“Here we go again,” Dean mumbled and Rowena grinned as she filled up the Alpha’s coffee cup before handing him another muffin. He took it with a small smile and bit into it, his eyes fluttering shut. 

Those magic muffins were damn good.

Gabriel reached out for the last chocolatey treat and Rowena slapped his hand. “No,” she shook her head. “No muffin for you after the way you behaved in my house.” The Alpha grumbled under his breath and rubbed his hand. “Besides, you just asked your brother a question, you need to be more focused on his answer, than filling your belly with something sweet.”

“Fine,” Gabriel groused as he gave one final look of longing at the muffin before turning his attention to Castiel.

“Dean is,” Castiel blew out a deep breath and stared into his brother’s whiskey colored eyes as he pressed on, “Dean is my true mate.”

“Seriously?” Gabriel’s jaw dropped as he stared at the couple. A huge smile spread across his face as he whooped. “Congratulations!” He leaned across the table and slapped the other Alpha on the shoulder. “Welcome to the family, Dean-o.”

“Thanks,” Dean muttered, rubbing the spot Gabriel just smacked as he grimaced at the ridiculous nickname.

“Soooooo,” Gabriel grinned as his eyes flickered back and forth from Dean and Castiel. “How’d ya meet?” He asked as he snatched up the muffin that had been taunting him and crammed it in his mouth.

“We met last night.” Castiel shifted in his seat and reached over to take Dean’s hand in his. He needed his Alpha’s touch, it gave him strength, kept him grounded. “During my Rite.”

“Really?” Gabriel laughed spewing muffin pieces out onto the table.

“Animal,” Rowena sighed as she swept them up with her hand and deposited them on the empty plate.

“That’s, just wow,” Gabriel’s grin turned impish. “So did your Dean here watch as you sang the Alpha to the sea?” He licked the chocolate from his fingers before adding, “Did it make him all hot and bothered, and as soon as you were finished he dragged you off to a nice secluded cave?” Gabriel waggled his eyebrows, “That would explain why you guys reek of each other.”

“Not quite,” Dean snorted into his mug as he side eyed Castiel with a smirk and mumbled, “but we did spend the night in a cave.”

“Ohhhh,” Gabriel leaned forward crossing his arms on the table. “So what exactly happened, Cassie?”

“Dean didn’t _watch_ me sing the Alpha to the sea.” The Siren reached up and ran his fingers through his hair as he sighed. “Dean _is_ the Alpha I sang to the sea. He’s the one I chose.”

Gabriel’s nose scrunched up in confusion. “Huh, what are you talki- Oh! Oh!” His eyes widened in realization as his gaze snapped to Dean’s throat then back to his brother. “You used your wish! You used your wish to save him, didn’t you?”

“Yes,” Castiel nodded as he stared over into his mate’s eyes. “He’s my true mate, Gabriel. I would have given _anything_ to save him. Including my one wish.”

“How’d you figure it out?” Gabriel whispered as he studied the true mates.

“I scented him just as he went under.” Castiel huffed a small laugh, “Then I dove in immediately after to save him.”

“Dad is _so_ gonna be pissed.” Gabriel shook his head, amusement dancing in his eyes as he continued. “Not only didn’t you complete your Rite of Passage, the intended you chose to sacrifice ended up being your true mate, and you used the wish mom gave you to save him and turn him into a Mer.” He paused for a beat then added. “Not to mention Dad is the one who’s supposed to find a suitable mate fo-.”

“Triton would not stand in the way of true mates.” Rowena chimed in as she looked into her youngest nephew’s worried eyes. “I’m sure of that, Castiel.” She added with a tone of certainty in her voice. Castiel gave her a curt nod but his stomach still turned with uncertainty.

“Oh!” Gabriel exclaimed, drawing everyone’s attention back to him. “And let’s not forget tonight’s festivities. The castle is absolutely bustling this morning to prepare for the banquet in your honor tonight, Castiel. You know,” Gabriel clicked his tongue, “the one for completing your Rite.”

“Is that something that is done for all Sirens when they complete their Rite of Passage?” Dean asked as he popped the last bite of his muffin in his mouth.

“Yeah,” Gabriel nodded. “Most are held in the big silver temple in the middle of town. But since Castiel, here, is a crowned prince, his will be held in the palace, and a bit more grandiose than others.”

“Shit,” Castiel groaned as he let his head fall forward and thump against the table. “I forgot all about the banquet.”

Gabriel blew out a breath and shook his head “I would not want to be in your fin right now.”

“Gee, thanks for the support.” Castiel deadpanned as he sat back up and leaned into Dean for comfort. The Alpha’s hand immediately found its way to the nape of his mate’s neck, where he gave a gentle reassuring squeeze.

“You have mine,” Rowena assured as she reached across the table and patted Castiel’s hand before looking over at Dean, “and so do you.”

“Thank you,” Dean and Castiel said in unison.

“Oh, come on,” Gabriel huffed and waved his hands in front of them. “You’re my little bro, you’ll always have me in your corner. You know I’m gonna support you in anything you do.”

“I know,” Castiel nodded and smiled. “You always have.”

Rowena smiled at her nephews for a moment before she raised up and gathered all the dishes from the table and placed them on the tray as she cleared her throat, “As much fun as this has been, you need to get back to the castle Castiel, before your father begins to worry.” She picked up the tray, swam over to the counter and sat it down before turning to face them. 

“Before you go though I need to spell Dean’s necklace to where it just looks like an ordinary conch shell necklace. Your father would surely notice it as Cordelia’s, look how quickly Gabriel did. And,” she flitted over to her nestside dresser and opened her jewelry box, pulling out a Tiger Puka shell choker. “You need to put this on and I can spell it to look like your mothers.”

“Okay,” Castiel replied as he and Dean swam over to her. Castiel took the necklace from her hand a fastened it around his throat.

“Ready?” Rowena asked, waiting for the mates to nod before she reached up and placed a palm to each necklace as she whispered a short incantation under her breath.

Dean waited with bated breath wondering if he would feel anything from the spell. After a moment Rowena removed her hand with a smile. The Alpha looked to his Omega then back to the Sea Enchantress. 

“That’s it?” Dean glanced down at his necklace and frowned. “I don’t think it worked, it looks the same.”

“Of course it worked,” Rowena rolled her eyes and placed her hands on her hips. “I just made sure to add into my little spell that the little glamour didn’t affect you or Castiel.” That necklace,” she nodded to Dean’s throat, “was the very first gift given to you by your mate. I figured you wouldn’t want its true form hidden from you.”

Dean mulled over her words, and his inner Alpha immediately agreed with her. That necklace was special, given to him by his Omega. It not only meant a lot to his mate, but had saved his life, and the thought of its beauty being hidden from him, made him feel melancholy. 

“You’re right,” Dean reached up and caressed the inky pearl. “Thank you.”

Rowena gave him a curt nod before clapping her hands together. “Oh, one more thing!” She turned back to her dresser and pulled out a vial filled with purple liquid. She pressed it into Castiel’s hand as she spoke. “You and Dean place one drop on your mating gland every morning and it will mask the smell of the other on your skin. Only the two of you will be able to smell your mingled scents.” She gave them a small smirk, “Best use it now before heading to the castle.”

Rowena swam over to Gabriel as Dean and Castiel each placed a drop of the potion where she had instructed. She wrapped her eldest nephew into a hug and whispered in his ear. “Keep them both safe.”

“Promise, Aunt Ro,” he whispered back and placed a kiss to her temple.

Dean and Castiel joined them a moment later and Gabriel scented the air to make sure the potion work. With a thumbs up from the Alpha, Rowena shooed then out the door with a promise she’d see them that night at the festivities.

As the trio swam towards the palace Gabriel glanced over to Castiel, “How the hell are we gonna get Dean in without the guards and dad being suspicious?”

“I have an idea,” Castiel gave his mate a small smile before he grinned impishly over at his brother, “but I’m really gonna need you to pull it off, Gabriel.”

  


  


“I can’t believe that worked,” Gabriel hissed as he followed Dean and Castiel into his brother’s room, closing the door behind them.

“Told you it would,” Castiel smirked over his shoulder. “The past two Theros Times you have visited Uncle Chuck in Parádeisos, it would make sense you made friends there. And friends _do_ visit one another, so nothing strange about a fellow Mer dropping in to see an old friend.”

“Who knew you,” Gabriel snorted, “perfect little Castiel, could be so devious.”

“I did have the best to learn from.” Castiel gave his brother a pointed look as he swam over to his window seat. The Omega gazed over at his mate, who looked a bit shaken up. “Are you okay, Dean?” Castiel asked as he settled down on the bench.

“That was scary,” Dean shuttered as he joined his mate. “Are all Atlantian guards like that?”

“Nope,” Gabriel shook his head. “Gadreel is a puppy compared to some of the others.” He flopped down in Castiel’s nest and smirked at the other Alpha. “And just wait til you meet our father.”

“Gabriel,” Castiel chided as he reached over and took his Alpha’s hand. “Stop trying to frighten my mate.”

“Oh, Gods,” Dean croaked. “He’s gonna know!” He met his Omega’s eyes, his own wide and fearful. “He’s going to take one look at me and just _know_.”

“No, he won’t,” Castiel leaned in and nuzzled his Alpha’s throat. “My father will believe the story I came up with until the banquet is over. Then...” the Omega trailed off as he breathed in deeply, taking in his Alpha’s heady scent. “I will tell him about you.” Castiel sighed as he pressed closer to his mate. “I’m going to tell him everything.”

“You sure?” Dean whispered as he reached up and ran his fingers through Castiel’s hair. 

“Yes,” Castiel nodded as he leaned up and pressed a kiss to Dean’s lips. “I’m not keeping you a secret.”

“Gross, still here guys.” Gabriel mock gagged. “So no making out with me in the room.”

“Oh, please,” Castiel rolled his eyes. “That was chaste.”

“Still,” Gabriel dramatically shuddered. “I don’t wanna see some Alpha’s lips on my baby bro’s with a lusty look in his eyes.”

“Lusty?” Castiel purred as he glanced up into Dean’s eyes.

“Can’t help it,” Dean growled. “You’re sexy as hell with those big blue eyes and plush kissable lips.” The Alpha nipped his mate’s bottom lip before kissing him deeply.

“Seriously,” Gabriel whined like a youngling. “Stop that.”

Castiel chuckled as he broke the kiss, smirking at his mate’s dazed expression. “We best quit before we scar my brother.”

“Can’t he just go to his room for a while?” Dean gave his mate a charming grin. “Give us some time to get to know each other better?” The Alpha growled as he yanked his Omega flush against him. 

“Dean,” Castiel gasped as he felt heat pulse through his veins and his cock stir beneath his sheath. “That, uh,” the Omega shook his head trying to clear the carnal thoughts racing through his mind. Thoughts he had never had about an Alpha before, not even during his worst heats. “That would not be very wise.”

“Why not,” Dean pooched his bottom lip out, pouting. “Don’t you trust me,” the Alpha teased.

“It’s not you I don’t trust,” Castiel whispered as he licked his lips and willed his libido to calm before Dean, and God’s forbid, Gabriel, were able to scent his arousal.

“Besides,” Gabriel chimed in, “how would it look if some stranger, and an Alpha at that, was left alone in the bedroom of the Omega crowned prince?” Gabriel quirked a brow as he scrutinized the mates. “And what if dear ol’ dad comes looking, and just happens to wander in on his baby boy in a compromising position with said Alpha?” 

“He’s right,” Dean cleared his throat and huffed out a small laugh. “That is not the first impression I want your father to have of me.”

Gabriel snorted at the same time a loud series of barks sounded outside of Castiel’s door. The Omega’s face lit up and he glanced over at his brother. “Go open the door and let Finn in, please.”

“Lazy,” Gabriel grumbled as he shifted out of the nest and swam over to the door.

“Not lazy, just extremely comfortable,” Castiel retorted with a smirk.

The Omega cuddled against Dean’s side just as his brother twisted the knob. Finn barreled in, knocking Gabriel backwards. The Alpha grunted and glared at the sea lion as he closed the door.

“Little fucker,” Gabriel muttered. “Can’t tell me he doesn’t do that shit on purpose.” The Alpha flitted back to his brother’s nest and flopped down with a glare aimed towards Finn, who was currently finagling his way in between Dean and Castiel.

“Finn,” Castiel chuckled as he scooted over making room for his pet. The sea lion barked happily when he was able to lay his head in the Omega’s lap. Castiel shook his head fondly and patted his head.

“I think somebody is jealous.” Dean stated with a raised brow as he stared down in amusement at the hind flippers that were currently trying to push him further away from his mate. “Must be used to getting all your TLC, huh, Cas?” 

Castiel nodded as he grinned at his pet’s antics. 

“Well, buddy,” the Alpha leaned forward so he could meet Finn’s eyes. “You’re going to have to learn to share.” Finn lifted his head and glared at Dean, barking forcefully at him twice before laying back down in Castiel’s lap.

“Good luck with that,” Gabriel snorted as he met Dean’s eyes. “He’s a possessive little asshole that hates Alphas.”

The Omega ignored his brother in favor of gently scolding his pet for his zealous behavior towards Dean. “Finn.” Castiel shifted the sea lion to the other side of him, and he scooted closer to Dean. “This is my mate, and I can give him attention too.” The Omega leaned down and pressed a kiss to Finn’s snout as he whispered so low only the sea lion could here, “I have plenty of love to go around.”

Finn wiggled his way onto Castiel’s lap. He glanced up and Dean before dipping down and nudging the Alpha’s folded hands that were resting in his lap.

“What?” Dean asked the sea lion as he continued to huff and prod at his hands.

The Omega chuckled, “He wants you to pet him Dean.”

“Oh,” the Alpha nodded as he lifted his hand up pausing as he stared down at Finn. “You’re not going to bite my hand off are you?” When all he got in lieu of an answer was an impatient snort and another nudge to his hand he patted the sea lion on the head.

A smile spread across Dean’s face as Finn pushed into it. He ran his hand along the top of Finn’s head, and scritched behind his ears. “You’re kind of cute,” Dean cooed as the sea lion plopped his head down in the Alpha’s lap.

“Looks like he likes you.” Castiel grinned at the sappy look his Alpha was giving Finn as he petted him. The Omega laid his head on Dean’s shoulder and ran his fingers through the short fur along Finn’s back.

Dean smirked over at his mate, “I can charm anything.”

“That’s not fair!” Gabriel sputtered. “I give that mutt treats all the time and all Dean has to do it pat his head and scratch behind his ears and suddenly they are besties? Bullshit I say!”

“Gabriel, don’t be so jellyfish,” Castiel teased with an impish grin. “Dean’s just way more alluring than you.”

“Again, I call bullshit. No one puts on the charisma like me.” Gabriel crossed his arms around his chest as he concluded, “Finn just knows Dean’s gonna be banging his master so he needs to get on his good side, that’s all.”

“Yeah,” Castiel deadpanned. “I’m sure that's it.”

Dean laughed at the brothers’ jesting as he continued to pet Finn. Watching them together made him think of Sam. He missed Sam. Though he just talked to him the other night it had been about three months since they’d last seen each other. During their last conversation they had been making plans for him and his wife, Jess, to visit soon. 

Now Dean was left wondering if he would ever see him again. He let out a soft sigh, he couldn’t think of such things right now. He didn’t want to ruminate on the fact that when Rowena came to him with the spell to reverse this one he would have to make the choice between his life on land, of being able to see his brother and uncle Bobby again, or being with Cas, his true mate. Deep down he knew which he would choose in a heartbeat, but again, he didn’t want to think about that right now. So in true Dean Winchester fashion he pushed all those thoughts from his head, and focused on something else, another more immediate pressing matter.

Dean cleared his throat, gaining the brothers’ attention. “When does this big shindig start?” 

“Soon,” Castiel sighed as he looked out the windows and down at the clusters of Merfolk swimming towards the castle. “People are starting to gather.”

“So, um,” Dean drew his bottom lip into his mouth and chewed at it in an agitated manner. “Is your dad going to be the one to come and get you?”

“What's a matter, Dean-o?” Gabriel gibed with a cocky leer. “You’re acting all skittish, is a big bad Alpha like you _actually_ nervous?”

“Well, yeah.” The Alpha answered immediately. “Not only is he the King of Atlantis, he’s my true mates father. What if he doesn't like me?” He glanced over at Castiel, “what if he thinks I’m not good enough for you?”

“Not possible,” Castiel reached up and placed his hand on his Alpha’s cheek. “I know I’ve only known you for a day but I can tell by your aura that you’re an amazing man, Dean Winchester.”

“My what now?” Dean queried as he crinkled his nose in confusion.

“Aura,” Castiel repeated. “It’s a distinctive atmosphere that surrounds the being it’s created by.” 

“Creepy right?” Gabriel piped up as he flicked his bronze and golden fin in the sand. “Siren’s are able to get a read on a person just by looking at them.”

“That’s not always the case,” Castiel looked to Gabriel then back to Dean. “Some auras are fuzzy, muddled, some just show us they are an Alpha, but not what kind of person they are.”

“What do you see in mine?” Dean asked as his fingers trailed down the slope of Finn’s back and met his mates.

The Siren tilted his head to the side studying his mate. “Yours is incredible. It’s a whirling combination of blue and green. It radiates devotion and honesty, peace and,” Castiel’s tone dropped to a whisper as he stared into the depths of Dean’s emerald eyes with a smile, “Love.”

Dean opened his mouth to speak but was cut off by a sharp knock on the door. 

“Prince Castiel,” a deep voice resonated from the other side.

“Yes,” the Omega called back as he glanced over at Dean who had moved to the very edge of the bench as far away from him as possible. Castiel smirked and shook his head as he continued, “What do you need Ion?”

“It’s time for the banquet, my prince.”

“Thank you,” Castiel answered his voice wavering slightly with nerves. He cleared his throat, “Gabriel is here with me, we shall both be down soon.”

“I will let His Majesty know,” Ion affirmed.

“Well,” Gabriel grinned at the high-strung looking mates, “let’s get this party started!”

  


  


The banquet hall was like nothing Dean had ever seen before. The floors were polished to a high shine the same as you’d see on land if the floor was marble. He wasn’t sure what material this was, but it was intriguing though, the way it glistened in a prismatic way. The walls shimmered as if coated in crystals and the column’s seemed to rise into an endless canopy. The windows were made of a variety of colorful sea glass. It very much reminded Dean of the stained glasses windows in the church he attended with his family when he was a boy.

Long wide tables filled the hall side by side, eight deep. There was enough room to fit hundreds of Merfolk comfortably. Each table was set just so with golden plates, goblets, and utensils. The grandeur of it all, shouted ‘royalty’. Dean sucked in a deep breath as he surveyed the breadth and depth of the banquet hall. He had been a successful businessman, had plenty of money and power in his electronics company. But this? This was something else entirely, a whole new level of luxuriance. He felt completely out of his element.

“Looks like daddy-o out did himself, hm?” Gabriel clapped his hands together in delicious expectation.

“Gabe!” Cas hissed, “Show a little decorum. Please!”

Dean ignored the two brothers. He was used to brotherly bickering. His eyes were already feasting on the numerous dishes still being brought out. Long trays heaped with lobsters and shrimps. Bowls of steaming potatoes, his favorite vegetable, followed closely behind. Then another long platter came out with some sort of roast, beef or pork, he wasn’t sure from this distance, but the scent wafting from it was delectable. The number of other dishes being displayed seemed endless. The delicious aroma made Dean’s mouth water.

Castiel took his arm, “There will be more food than you’ve ever seen, but first,” he propelled him forward, “we need to introduce you to father, so he doesn’t think we are keeping you from him.” The Siren gave Dean a small smile, “He can get suspicious over the tiniest things sometimes. So, better now than later.”

“Great,” Dean muttered as he allowed his mate and Gabriel to push him onward towards the King.

Castiel’s father, Triton, was an imposing Merman and an intimidating Alpha. His long thick goldenrod yellow tail made him taller than most of the Merfolk, and he wore his age well. The only give away was the steely salt and pepper hair and beard, that while a mark by age, retained the fullness of his youth. Behind the stoic visage, Dean saw both cunning and wisdom. Dean was struck by the icy blue eyes that held a hint of warmth. In a way, they reminded him of Castiel’s, but in others not so much. Like now, they bore through him in a distrusting manner that made Dean want to squirm. 

They were the eyes of any distrustful father, but this one was a king and if Dean wanted to forget that little fact, the crown atop his head was an eloquent reminder. It was beautifully adorned with pears of different colors, but those spiky shells, they looked fearsome. 

His Majesty listened keenly as Gabriel told the tale that Castiel had woven for their father and any others who raised questions about Dean. Dean tried hard to keep the steel-winged butterflies flapping in his belly at bay as His Majesty’s gaze pinned him where he stood. Even though he was an Alpha, he still had a strong impulse to submit to the imposing monarch. And Dean wasn’t quite sure what to make of that. Alpha’s submitted to no one. But he knew to make a good impression on his mate’s father, and to be respectful of Triton’s status, he’d have to submit, after all, the man was royalty.

Dean’s stomach clenched in anxiety at the look in the King’s eyes. It was as if His Majesty knew something was off. As if he was waiting for just one inconsistency in Castiel’s story to latch onto and prove it false. But Gabriel deftly relayed the tale Castiel had created. And Dean had to concede that Gabriel was truly blessed with the silver tongue of a master storyteller.

When Gabriel finished Dean let out a small sigh of relief. His Majesty had yet to say a single word, but gave his eldest son a terse nod and turned his sharp gaze to Dean. Triton blatantly surveyed him, waiting for the other Alpha to make a move. As Dean bowed, the king grinned in regard to the respect the Alpha had given him. With a last glance into Dean’s eyes and a curt nod, he turned his attention to Castiel. He pulled his youngest son into a hug with a beaming smile. Although he had some reservations about the tale he’d been told, he was every bit the proud father. And tonight was to honor his son and their traditions, he would learn more about the stranger later.

When it came time to be seated, Castiel was given the place of honor on his father’s right. The Omega and Gabriel ushered Dean to the seat between them. Dean shifted in his high backed chair at the curious gaze leveled at him by His Majesty. Dean’s fingers twitched, wanting to reach out and touch Castiel. He held them firmly in his lap though. The last thing he needed to risk was his mate’s father catching them before he knew the truth.

Rowena joined them shortly after, taking the seat on the other side of Gabriel. As the banquet hall filled to capacity, chatter and laughter echoed off the vast walls. Trays of food and decanters of wine were liberally passed around. Everyone began to fill their plates and goblets with the exquisite delicacies prepared by what had to be a huge kitchen staff. 

Despite Dean’s nervousness he piled his plate high, loading it down with roasted duck, lobster tail, braised beef, fingerling and mashed potatoes, glazed carrots, green beans, cream style corn, and black bread rolls. Everything was as delicious as it looked and smelled. The duck melted in his mouth, the beef could be cut with a fork, and the mash potatoes were creamy and lump free. Not to mention all of it was seasoned perfectly, maybe Rowena had been right, maybe magicked food was better.

“Looks good,” Castiel whispered as he eyed his mate’s plate with a small smirk. “Here,” the Omega picked up the silver decanter in front of him and filled his Alpha goblet. “Try that, it’s a honeyed wine.”

Dean picked up the glass and eyed the red liquid before taking a sip. “It’s good,” he hummed. “Sweet.” The Alpha glanced past his mate to the King who was busy conversing with the two men on his left. He looked back to Castiel with a smile and lowered his voice to where only his Omega would here, “But not as sweet as your lips.”

“Dean,” Castiel gasped flushing as crimson as the wine.

The Alpha’s grin grew at the bright blush that painted his mate’s cheeks. “What I wouldn’t give for another taste.”

“Later,” the Omega gazed at him through his long lashes. “You can taste as much as you want.” Castiel licked his lips and leaned a little closer to Dean, “ _Anywhere_ you want.”

Dean picked up his goblet and drained it. The Alpha stared at his mate, his pupils dilated with desire. “I’m holding you to that, Cas.”

“Please do,” the Siren mumbled as he turned his attention back to his plate. A small smile played on his lips as he felt the heat from his Alpha’s stare.

“Dean,” Rowena hissed drawing the Alpha from lusty thoughts his mate, he looked over to the Sea Enchantress. She smirked at him as she held up a tray. “Sushi,” Rowena asked with a smirk.

Dean snorted as he eyed the assortment. He matched her smirk as he reached past Gabriel, grabbing a California roll, and popping it in his mouth. “Mmm,” he moaned as he chewed.

Rowena rolled her eyes as she laughed and placed the tray down. “So,” she took a drink of wine, “what do you think of Atlantis so far?”

Dean swallowed the roll before answering. “It’s amazing.” He glanced over his shoulder at his mate who was smiling at something his father had just said to him, then back to Rowena with a look of pure adoration in his eyes. “Everything about it is _amazing_.”

“Awww,” she cooed, knowing exactly what Dean had meant.

“That was sickeningly sweet,” Gabriel mock grumbled, but a smile spread across his lips. “Cassie deserves the whole nine though, romance and all that jazz.”

“He does,” Dean acknowledged as he nodded. “That’s why I’m gonna be the best damn Alpha I can for him.” He looked from Gabriel to Rowena, “And I’ll spend every single day showing him just how special he is, and how much he means to me.”

“You’ll do just fine for our Castiel,” Rowena hummed as she polished off her wine. 

“Agreed,” Gabriel concurred as he rubbed his hands together. “Now who’s ready for dessert?”

Dessert was just as delectable as dinner. The dining staff brought out tray after tray filled with a variation of sweet treats. A colorful array of macarons, at least a dozen different types of tartlets in a variety of flavors, three cakes that stood at least four feet tall, and then there was the pie. More pie than Dean had ever seen in his life! In every flavor he could imagine, and Dean did his damndest to try a piece of each, however, he had to tap out on his eighth slice. There were so many more still left to sample but his stomach was starting to ache and he doubted hurling in front of his mate’s father would score him any points. 

“Impressive,” Castiel whispered out of the corner of his mouth as he subtly leaned closer to his Alpha and nodded towards his empty plate.

“Yeah, pie’s my favorite.” Dean whined as he wrapped his arms around his stomach. “But now I feel like I’m dying.”

“I could definitely tell pie was your favorite.” Castiel snorted and shook his head in amusement, “but, you know, I can get you pie from the kitchen anytime you want. There was no need to gorge yourself.”

“Now you tell me,” Dean mumbled as he glanced over to his Omega, who wore a huge smirk on his lips.

The sound of a chair scraping against the floor had both mate’s snapping their attention to His Majesty who was rising up to address his loyal subjects.

“Thank you for joining us today in celebration of this monumental occasion.” His Majesty’s voice boomed across the great hall. All in attendance fell silent and directed their attention to him as he continued.

“In our long lives as Merfolk there will be a many great Rites of Passage that will have a significant importance in our existence. Celebrations in honor of birthdays, matings, the birth of younglings, and in the life of a Siren,” he smiled down at his son, “singing their glorious death song for the first time, just as my Castiel did last night.”

Cheers erupted throughout the hall and Triton raised his hand to silence them before carrying on. “A Rite of Passage is a sacred ceremony in Atlantis. This ceremony marks the transition from one phase of life to another. It is important, a remarkable part of life as a Siren. It helps young Sirens feel more connected to their respective clan, makes their lives more fulfilling, and makes them finally feel like part of their community of fellow Sirens who have endured the Rite.”

Triton placed his hand on Castiel’s shoulder, giving it a gentle squeeze before grinning down at him. “I’m very proud of my son.” He looked back to the crowd of Merfolk, “As Atlantians I’m sure you are as well, so let's give him a round of applause to show just how proud of him we are.”

Castiel tried very hard not to shift in his seat, tried hard to smile and nod at the crowd as the clapping and shouts of congratulations grew louder. But he didn’t deserve this, he had failed his Rite, he had let his father, and the fellow Sirens of Atlantis down by choosing the one land Alpha there was no way he could kill. The Omega didn’t have long to wallow in self-pity before his father was raising his hand and quieting the crowd once again.

“I have another announcement.” His Majesty motioned to the two men on his left, who immediately rose as soon as the King looked their way. 

Dean studied the two Mers closely. They were both Alpha’s, he could tell that by one sniff. The one closer to the King was clearly older. He had dark hair and brown eyes, his tail a bit shorter than most Merfolk. The color of it was dark like Castiel’s, but not as radiant, it reminded Dean of ashes, a dull grayish black. But the way that he smirked had Dean instantly thinking he was a smug bastard. 

The other Mer, by looks alone, Dean assumed was around his age. He had the same dark hair and eyes as the first, which made Dean wonder if they were related. The second Alpha also had a strong jawline, and a look that suggested dominance. His tail, unlike the other Mer was longer. It was a rich hickory color, and by the ardent looks he was receiving from a lot of the Beta and Omega Merfolk in the crowd, he was clearly considered a handsome Alpha.

Dean took an instant dislike to the Merman. It wasn’t the looks he was receiving that irked Dean, he could care less about that. It was the looks he was giving Castiel, _his_ Omega, _his_ mate.

Triton held out his hand to Castiel and he took it, allowing His Majesty to pull the Omega up to his side. Castiel glanced back at his mate in confusion before turning his gaze to his father who began to speak again.

“The Sea Enchanter, Crowley, came to me a few months ago and informed me his son, Arthur, was ready to take a mate.” His Majesty smiled at Arthur, who returned it, along with a small bow. “I was overjoyed by the news and immediately thought back to how Castiel and Arthur had grown up together, how they had played together when they were younglings, and how they are still close even to this day.” 

The Omega stared up into his father's eyes that were beaming with pride, and a little bit of melancholy. “Castiel,” he gave his son’s hand a squeeze as he continued. “It’s been an honor being your father and watching you grow into a wonderful young Omega. Now that you have passed your Rite, now that you are a full-fledged Siren, the time has come for me to stop holding you so closely.” 

Triton reached up and wiped a tear from his eye. “It’s time for you to start a family of your own, give me some grandchildren.” He chuckled at the flush spreading across Castiel’s cheeks. “So as your father, I have chosen a mate fit for you, Prince Castiel. I give your hand, to Arthur, son of Crowley, the Sea Enchanter, to claim you as his with my blessing.”

Crowley and the King shifted back as Arthur moved in front of Castiel and cleared his throat. “Omega,” Arthur held out his clenched hand in front of Castiel. He opened it slowly, revealing a ruby as big as his palm. “Accept this gift and me as your Alpha.”

Dean moved to lunge at the other Alpha but was held in his seat by Gabriel’s strong hand clamping down on his shoulder. “No,” Gabriel whispered as he shook his head. “You will only make matters worse. This is something Castiel is going to have to take care of on his own.”

“Okay,” Dean grumbled as he nodded, not wanting to make things worse for his mate, even though his inner Alpha was still roaring at him to rip the other Alpha to shreds. He took a deep breath and looked to his mate, trusting in him to handle the situation.

“I-I,” Castiel stuttered as he glanced out at the crowd, then down at the jewel, to his father, then back to Arthur. His heart was pounding in his chest and he couldn’t hear anything over the sound of his blood rushing in his ears. He took a few deep calming breaths, knowing what needed to be done. He couldn’t accept, no matter if it was their way. He couldn’t accept Arthur as his mate. He didn’t want him, even if his father had chosen him, had deemed him worthy. He wanted Dean, his true mate, the only Alpha to whom he will ever want to sing songs of comfort and seduction. And when his father got to know Dean he would see that he was a better fit for Castiel, that he was the only one good enough as far as the Omega was concerned.

Castiel straightened up, held his head high as he looked into Arthur’s eyes. “I can’t Arthur. I can’t accept the gift, or you as my Alpha. I truly apologize.” Castiel turned at met his father’s bewildered gaze, “I’m sorry, father, I cannot mate with him.”

**Notes for the Chapter:**

> Hope you enjoyed the chapter!
> 
> [ _**Graphics Masterpost created by ZephyrChrysalis here!**_ ](https://archiveofourown.org/works/15728604/chapters/36566784)


	5. Chapter 5

**Notes for the Chapter:**

> Big thanks to Ani-make-me-girl for beta’ing this chapter, and zephyrchrysalis for Alpha reading and providing art.
> 
> This chapter is another long one!
> 
> Enjoy! :)

**“You’re the ocean**

**and**

**he’s desperate to drown.”**

**Michelle Hodkin**

You could hear a pin drop in the great hall after Prince Castiel’s declaration. Arthur looked confused, Crowley looked furious, and Triton was a mixture of both.

“You what?” His Majesty asked, his tone laced with ire. “I have chosen this Alpha as your equal and you say you can’t mate him.” He leaned closer to Castiel, “you better have a damn good reason.”

“I-I do,” the Omega nodded as he licked his lips and glanced out over the crowd that was watching with curiosity. He looked back to his father's eyes, pleading, “Can we talk about it later?”

“No, we shall talk about it _now_ ,” Triton hissed before turning to his loyal subjects. “Thank you for joining us in celebration today, but the festivities are now over. I need to speak with my son, _alone_.”

Castiel swished his fin nervously as he waited in shocked silence as the Merfolk filed out of the great hall, murmuring about the night’s unexpected turn of events. The Omega couldn’t even look his father in the face. He didn’t want to see the anger, frustration, and hurt. And _Gods_! Most of all he didn’t want to see in his father's eyes how disappointed he was.

There was nothing else Castiel could have done, though. There was no way he could have accepted Arthur as his Alpha, not when he already had one. The Omega found himself wishing he had told his father the truth about Dean before the damn banquet. At least then he would not have shamed his father publicly by turning down the Alpha he had chosen for him. As an Omega you accepted the mate your father, or family Alpha chose for you. You never questioned their ability to pick out a good match for you, especially if you were the son of the King.

Castiel risked a glance at his father and instantly wished he hadn’t. He was currently in a very heated argument with Crowley. Castiel’s stomach twisted. Not only had he caused a scene, but also created problems for his father with one of the most powerful Sea Enchanters in all of Atlantis. Could this evening get any worse?

The Omega gasped and flinched when he felt warm knuckles grazing up his spine. He turned to his right to see his Alpha standing there. “Dean,” the Omega gave him a small smile, “what are you still doing here? You should go with Gabriel. I will find you after I explain everything to my father.”

“No,” Dean shook his head. “No way in hell am I leaving you to do this on your own. We’re mates and that means we stick together,” a small smile lifted his lips, “Through the good and the bad, the happy and the sad.”

“Thank you,” Castiel whispered as he leaned into his mate’s touch, not the least bit worried of his father noticing because he was still bickering with Crowley. He relished in the physical contact for a few moments before being pulled into a hug by his brother. 

Gabriel leaned closer and murmured Castiel ear. “I’ll be in my room, come find me after. I’m here for you not matter what happens, or what you choose to do.”

“I know, and I appreciate it.” Castiel replied as he squeezed his brother tighter. Gabriel pulled back and gave Dean a reassuring slap to his shoulder before turning and swimming from the room.

“I’m staying with you too.” Rowena announced from Castiel’s left side where Gabriel just vacated.

“Aunt Rowena,” Castiel gave her a grateful smile, feeling stronger with his mate and his aunt by his side. “I don’t know what to say.” 

“You needn't say anything,” Rowena reached up and patted Castiel’s cheek. “We are family,” she glanced past him to Dean. “You too.” Rowena grinned at the mates, “And I stick up for my family when they need it.”

The trio looked over just in time to see Crowley swimming out of the room in indignation. Arthur followed closely behind, casting one last pining look in Castiel’s direction.

“What are you two still doing here?” Triton’s voice thundered as he glanced from Rowena to Dean. “I said I wanted to speak to my son in private.” His Majesty swam closer, pausing in front of Dean and studying him with narrowed appraising eyes. It took everything in Dean not to flinch. “What business would _you_ have being here at all?”

Both Dean and Castiel opened their mouth to answer but were interrupted by Rowena swimming in front of the mates and meeting the King’s steely glare with one of her own. “Trust me, Triton,” she crossed her arms over her chest. “Dean and I both need to be here with Castiel for you to understand the whole story, to fully comprehend everything that has led us here, to this moment.”

“Somebody start explaining what is going on right now!” Triton bellowed in frustration. 

“No need to yell,” Rowena tsked as she placed her hands on her hips. “Let’s all have a seat and talk,” she shot a glare in the King’s direction. “In a civilized manner.” 

“Alright,” Triton conceded as he swam over to his spot at the head of the table. The others followed, sitting down across from him with Castiel in the middle. “Well,” he quirked a brow at the trio.

“Okay, I’ll start, since this all begins with me.” Rowena sighed as she shifted in her seat. “A little over a year ago I cast a spell.” She folded her hands on the table. “One to find Castiel’s true mate.”

“How could you mess with such magic,” Triton admonished. “The Gods could have punished you, taken away your magic!”

“I was willing to risk it, I made a promise!” Rowena shouted in irritation. She took a deep breath and lowered her voice, sparing a glance at her nephew and his mate as she continued. “Cordelia made one request of me on her deathbed. She made me promise to try and find Castiel’s true mate when the time felt right. Because unlike Gabriel who gets to choose whomever he wants, Castiel’s decision is out of his hands.” Rowena shook her head at the indignant glare Triton was giving her, “Now don’t give me that look, Cordelia or I neither one had any doubts that you would pick a fine Alpha for Castiel. But she didn’t want just any Alpha for her baby boy. She wanted his true mate.” She pursed her lips and canted her head at the king, “Do you know why?” 

“No,” Triton looked to his son then back to Rowena. “Tell me?”

“Because,” she glanced up into Triton’s eyes, “she wanted him to live a life full of love and happiness like she had with you, her true mate.” 

Castiel reached for Dean’s hand under the table and held it tight. The Omega turned his head and smiled at his Alpha, who in return smiled back. His mother had wanted this for him, had wanted him to have the same happiness as she had with his father. Gods he wished he could hug her, and thank for the role she played in bringing Dean into his life. Wished she could meet the Alpha that was marked by the Gods as his. She would have loved Dean, he’s sure of it.

“You,” Triton rumbled as his gaze snapped over to Dean. “It’s you isn’t it? You’re Castiel's true mate.” He eyed Dean earnestly, “Gabriel may be blessed with a silver tongue but I’m a master at smelling bullshit from a mile away. I knew there was something off with the story he told me.”

“I…” Dean’s voice cracked, nerves getting the better of him. He cleared his throat and began again. “Yes, I’m Castiel’s true mate.”

“You’re not from Parádeisos, are you?” Triton asked as he leaned forward, eyes not leaving the other Alphas.

“No, Sir,” Dean shook his head, his hand clutching Castiel’s as hard as possible without hurting his mate. “I’m not.”

“Are you from Purgatory?” Triton narrowed his eyes. “Because true mate or no, if you are from there, I don’t think I could give my blessing. The way they treat their Omegas is downright savage.”

“I assure you I’m not from there either.” Dean subconsciously shifted closer to his mate, earning a frigid glare from Triton.

“Then where, where are you from?” Triton crossed his arms over his broad chest. “Don’t even think about lying to me, because I’ll know.”

“Well, you see, I, umm, not from around here exactly.” Dean floundered, unsure of how to explain to his mate’s father that he wasn’t from the sea at all. 

“Dean is a land Alpha,” Castiel cut in, sighing as he met his father’s stunned gaze. “He was the one I chose for my Rite.”

“No! That’s not possible.” Triton shook his head. “This Dean is clearly a Mer, so why are you lying to me Castiel? I demand you tell me the truth right this instant.”

“He’s not lying to you,” Rowena assured. “And nothing is impossible,” she whispered as she leaned over and placed a hand each on the mate’s necklaces and muttered a spell, removing the glamour from them. 

“You didn’t,” Triton gasped as he stared at his wife’s necklace around the Alpha’s throat. “Tell me you didn’t Castiel! Tell me you didn’t use the wish your mother gave you to save some random land Alpha! How could you, a _human_!” His gaze snapped over to his son, eyes narrowed in disapproval. “And lying about passing your Rite? You have failed your fellow Sirens.” 

Triton growled as he reached behind his back and brought forth a large magnificent golden trident. Dean’s eyes widened in fear. Where the hell had he been hiding that! Triton brandished the weapon with finesse and ease as he pointed it at the Alpha. 

“I should end you now,” Triton snarled as he moved the trident closer to Dean.

“Be reasonable,” Rowena urged in a calm tone. “Don’t do anything you will later regret.”

“Regret,” Triton snapped as he pressed the weapon to the Alpha’s throat. “I would feel no regret in ending the life of a land Alpha, in the same way they would feel no such regret in killing one of our kind. So give me one good reason, human,” Triton sneered, “not to plunge my trident into your heart.”

“Triton,” Rowena whispered as she looked into his eyes, seeing the pain of his lost wife there. “They are not all like that.”

“Father, stop it!” Castiel cried out as he shoved the trident away from Dean and moved his body in front of his mate. “You want a good reason?” He glared at his father, “How about he’s my true mate, the one Alpha meant only for me, the one mother wanted me to find happiness with, the same happiness she had with you.”

“You have only known him for one day Castiel!” Triton clutched the weapon in his hand as he glared at the pair. “How could you be so foolish to automatically think he’s a good man?”

“His aura, it’s beautiful. Even though, like you said, I have only known him one day, his aura calls to me. It shows me he’s a good man, and a good Alpha.” The Omega looked at him pleadingly, “Father please, give Dean a chance. Mother would have, she would have believed me.”

Castiel shook his head sadly, “What would she think of you now? Of how you are acting? Do you think she would be proud? No.” Castiel held up his chin defiantly and met his father's stern gaze with one of his own. “She would be disappointed in how you are judging Dean before you have even gotten the chance to know him.” 

“Dammit!” Triton bellowed as he slammed his free fist, the one not holding his trident onto the table, knocking over goblets of wine. “I can’t do this now.” He ran his hand through his hair in frustration and he scowled icily at the mates. “I can’t process my son having a human as his true mate. I need time to think.” With those final parting words Triton rose from his seat, spun, and dashed out of the great hall, flicking his fluke so hard the waves from the force knocked over the remaining goblets that stood on the table.

Castiel watched the red wine spread across the table and dripped to the floor. His chest ached, he never fought with his father. They had always gotten along so well. His body quivered with a flood of adrenaline. He’d never raised his voice to his father before, and he’d most certainly never purposely tried to hurt him. His cheeks burned with shame at the way he used his mother as a weapon in their argument. 

Castiel was shocked with how angry he father had become. Sure he was uncertain how he was going to react to the truth about Dean, but he had never expected it to have been this bad. His father’s words rang through his brain again, and he felt his chest constrict with a fresh surge of anger. He knew a land Alpha was unexpected, but it wasn’t like any of the things he’d said were untrue. His mother would have believed him and she would have given Dean a chance! She definitely would have been disappointed in how quickly his father had jumped to condemn Dean for being human. She had always told them, ‘never judge a book by its cover.’ 

He grabbed onto the table just to ground himself, to steady his shaking hands. Truth be told he was still reeling that his father pulled his trident and threatened his true mates life, or that he would have looked at him with such disapproval in his eyes. How was he going to get through to his father? How could he prove that the Gods choose Dean for him for a reason. 

The Omega jumped when he felt a warm hand on his shoulder and he looked up to see Dean and Rowena were no longer sitting. Castiel sighed as he pushed himself up and threw himself into Dean’s waiting arms. The Alpha held him tight as Rowena wrapped them both into a hug.

“Castiel,” Rowena whispered and she reached up and ran her fingers through his hair. “Give him time, he will come around, deep down all he wants is your happiness, just as your mother did.” She pressed a kiss to each of their foreheads and flitted from the room leaving the mates still in a tight embrace.

After a few minutes of silence and the Alpha running his hand soothingly up and down his mate’s spine, Dean pulled back and whispered, “Cas, are you okay?”

“It’s a beautiful night,” Castiel said cutting his Alpha off, not wanting his sympathy. “Would you like to take a trip up to the surface?”

“Yeah,” Dean smiled as he pressed a gentle kiss to Castiel’s lips. “Sounds like fun.” The Alpha took his mate’s hand and let him led him from the room. He knew the quick change of topic meant Castiel wasn’t ready to talk about it just yet, and Dean couldn’t blame him. He probably still had a lot to process. One thing was for sure though, when he was ready to talk, Dean would be there for him, whatever he needed.

  


  


After about an hour or so of playing with Finn, who had followed the mates to the surface, Dean and Castiel moved closer to the shore. The place where Dean had spent most of his evenings waiting for Castiel. The two rested there side by side, waist deep in the water, watching Finn in silence as the sea lion continued to frolic on the rocks.

“You know, I’ve always been kinda envious of humanity.” Castiel whispered as he side-eyed Dean. “Since I was old enough to remember a part of me has wanted to travel on land, to see the world.”

“I’ve been all over the world, seen some amazing sites, but let me tell ya, Cas,” the Alpha smiled over at his mate. “By far, Atlantis has been the most _amazing_.”

Castiel hummed as he smiled back, his Alpha thought Atlantis had been the most amazing place he’d traveled. That made the Omega feel a twinge of hope. If Dean liked it so much, maybe, just maybe, he would be willing to stay there with Castiel. Make Atlantis his new home. But then there was the Alpha’s family. Would he be willing to leave them behind for him?

“You said you had a brother, do you have any other family?” Castiel queried curiously as Finn swam up barking loudly trying to get their attention.

“I do,” Dean answered with a nod and a small laugh aimed towards Castiel’s pet who was diving from the rocks and spraying water in the air above himself when he broke the surface. 

Castiel raised his fluke out of the water and watched the moonlight dance off of it. Observing as the deep blues bled into black before asking, “Will you tell me about them?”

“Alright,” Dean took hold of his mate’s hand, his thumb stroking the back of it as he spoke. “Besides my brother, Sam, there’s his wife, Jess, and our Uncle Bobby.” He knew Castiel was still deflecting, that he wasn’t ready to talk about what happened with his father yet, and that was fine by Dean, he was a patient Alpha. He could wait, so he continued on talking about his family. “My brother Sam, or Sammy as I call him, he’s four years younger than me, also an Alpha, and wicked smart. He’s just passed his bar to be a lawyer out in California where we both lived until I up and moved here. He met his mate, a pretty blonde haired Beta named Jess, who also just passed her bar to be a lawyer, about six years ago. They finally exchanged bites this past year.”

“Do you miss them?” Castiel murmured as his free hand sifted through the mud, searching for shells.

“I do,” Dean bobbed his head. “But we are used to going months at a time without seeing each other. When I lived in California. He had his life, I had mine, and our schedules rarely meshed.”

“What did you do?” Castiel inquired as he cleaned the mud from a Calico Scallop shell.

“Well, I owned a top-rated electronics company.” Dean smiled as he watched his mate handle the shell with such care. “I was kind of a big deal in the business world. That is, until I started having those dreams and sold everything to move here.”

“Do you regret it?” The Omega questioned, his eyes not leaving the shell that now rested in his lap.

“Cas,” Dean whispered as he reached up and placed his palm on his mate’s cheek and urged him to meet his eyes. When the Omega lifted his head Dean saw fear in those baby blues. Fear that his Alpha did regret it, and fear of being rejected. “Not for one second.” Dean shook his head, “it led me to you.” He leaned forward and pressed a kiss to Castiel’s lips.

The Omega let out a broken moan as Dean wrapped his arms around Castiel’s waist pulling him closer. They kissed slowly, languidly. It was sweet and gentle. Dean wanted this kiss to convey that he was glad his journey led him to Castiel, to his true mate.

Castiel’s lips were soft and tasted of salt, but they were utterly perfect, and made just for Dean. The thought that no one would ever kiss Castiel, or touch him the way he would had Dean’s inner Alpha roaring with satisfaction and pride. His Omega was beautiful, perfect, kind, and, not to mention, brave. The way he had stood up for Dean to his dad couldn’t have been easy, but he did it anyway. Yeah, Dean Winchester hit the true mate lottery with Castiel.

With all those thoughts of Castiel’s perfection swirling around in Dean’s mind the soft gentle kiss quickly turned deep and heated. Dean dipped his tongue out and ran it along Castiel’s plump bottom lip, nipping at it, asserting his dominance, asking his mate to open for him. The Omega’s root primitive urges kicked in and he parted his lips with a satisfied trill. 

Dean growled in triumph as his tongue swept in tasting his mate as they traced the contours of each other’s mouths. They kissed as the sea lapped up around them, Finn splashed and barked in the background. They parted only to scent mark, or to pepper kisses along each other’s jawlines and throats.

The sweet scent of aroused Omega began to fill the air around them. Dean breathed deeply taking in the divine smell, gasping when he felt the scales on his sheath part and the head of his cock push through. The Alpha pulled back and quickly placed his hands in his lap, but not before taking a quick peek. He said a silent thank you to the Gods that it looked the same as it did when he was all man.

“Why’d you stop,” Castiel slurred looking debauched and lust drunk.

“You were starting to smell so good.” Dean replied as he nodded down to his lap where his hands covered the beginnings of his erection. “A little _too_ good.”

“Oh,” Castiel whispered absent-mindedly. “Oh!” He repeated, his eyes widening when what Dean had implied registered in his lust addled brain. “Told you,” the Omega grinned impishly, “I told you the scales on your sheath would part and reveal your cock with sexual stimulation.”

“And you were right.” Dean grunted as he pressed down on his crotch, trying to will his erection away. “As much as I would love to ravage you, now is not the time for that.” The Alpha smiled shyly at his mate. “So my cock needs to go back into its sheath.”

“Alright,” Castiel snorted, amused by the situation. “Why don’t we take your mind off of it? Tell me about your Uncle Bobby.”

“Annndddd it’s gone,” Dean looked down at his lap, no signs of his arousal. “Welp, that’s one sure fire way to make my cock wilt, mention my uncle.” Dean laughed as he wrapped his arm around his mate.

“Glad I could help,” The Omega replied in a playful tone, chuckling when Finn splashed Dean in the face with his fore flipper.

“Hey!” Dean sputtered as he splashed the sea lion back. Finn huffed and barked before swimming back to the rocks. The Alpha turned back to Castiel. “Now, where was I again?”

“You were going to tell me about your uncle.” Castiel responded as he laid his head on Dean’s shoulder.

“Right,” Dean murmured with a small nod as he rested his cheek against his mate’s unruly hair. “Uncle Bobby is more like my father than uncle. He raised me and Sam from the time I was ten and Sammy was six. Our parents were killed in a car crash.” Dean held his Omega closer, breathing in his soothing scent, as he trudged on through the most painful experience of his life. “It was raining hard and they were on their way home from date night. A deer darted out in the road and dad slammed on his breaks, but the roads were so wet he hydroplaned and ended up in oncoming traffic. They were hit head on by a Semi, that’s a big truck for hauling, and dad, he died on impact, mom, she passed in the ambulance on the way to the hospital.”

“I’m so sorry for your loss,” Castiel whispered nuzzling at his mate’s throat, using his scent to comfort him, to alleviate some of the hurt talking about this painful memory caused. 

“When I was ten like you were, I lost my mother.” Castiel sniffled, the pain of reminiscing made his heart ache. He hadn’t talked about that day with anyone in years, but if his mate was going to open old wounds for him, he could do the same. “She was sunning on some rocks and fell asleep. The next thing she knew she felt a horrible pain in her stomach and she woke to a fisherman twisting a spear in her gut. She was an Omega, and therefore also a Siren, so she summoned what strength she had to sing.” Castiel let out a shuddering breath. “It wasn’t enough to kill the man but enough that she could get away. She made it back home but there wasn’t anything anyone could do for her.” His tone lowered to a whisper, “She said her goodbyes to all of us, and died that night.”

“I’m sorry for your loss, too, Cas.” The Alpha pressed a soft kiss to his mate’s forehead. “You know, even though it was over twenty-five years ago since the accident, not a day goes by that I don’t miss them.”

“I understand,” the Omega nodded. “I still miss my mother every day, too.”

Dean cleared his throat, thick with emotions before continuing where he’d left off. “Uncle Bobby was the one babysitting us that night, he’d been visiting us in Lawrence, that’s in Kansas,” Dean clarified for his mate. “Bobby was there for us through all of it, the crying, the denial, the funeral. He held our hands as the three of us said our final goodbyes to my parents, John and Mary.”

Dean blew out a deep breath as his fingers traced idle patterns on his Omega’s shoulder. “It was hard for all of us. But Bobby,” Dean smiled softly, “Even though he was a surly old Alpha, he was an amazing man. He decided uprooting us and taking us away from our home, school, and friends, wasn’t the right thing to do. Instead, he sold his home and garage, Singer’s Salvage Yard, it was located in Sioux Falls, in South Dakota, and moved to Lawrence, where he opened up a new shop. He called it Singer-Winchester Auto Repair, and he raised us like we were his own.” 

Dean huffed a small laugh. “I worked at the shop most evenings, and every summer break until I went off to college. To this day I still love working on cars. Especially my Baby,” Castiel looked up with a question in his eyes. Dean grinned, “She’s a beautiful sleek black 1967 Chevrolet Impala. I do all of her maintenance myself.” He smirked down at his mate, “I’m really good with my hands.” 

“I bet,” Castiel replied coyly as he reached over and stroked his Alpha’s fingers. “I’d love for you to show me one day.”

“Castiel,” Dean mock gasped as he placed his hand over his heart. “Are you flirting with me?”

“Trying,” the Omega teased back as he smiled cheekily.

“It’s definitely _working_ ,” Dean waggled his brows as he pecked Castiel on the cheek.

Castiel chuckled at Dean’s flirtatious charm as he licked his lips and met his Alpha’s eyes. “I was instantly drawn to you.” The Omega whispered in awe. “From the moment I saw you, I had this intense need deep within to sing for you. But I messed it all up.” He shook his head, “I had no idea what I was feeling was a pull to my mate, and the urge to sing you songs of comfort and seduction. I thought it was my inner Siren emerging, and the need I felt was to sing you my death song.”

Dean dug his fluke in the sand as he glanced over at Castiel. “You have different songs?”

“Yes,” the Siren nodded. “We have our death song, which you know is to lure land Alpha’s into a watery grave. Then we have our song of...” he peered at his mate through his lashes bewitchingly as he purred, “comfort and seduction.”

“So you’re telling me,” Dean leaned in closer and ran his fingers down his Omega’s spine. “That you can seduce me through song?”

“Yes,” Castiel hummed as he arched into his mate’s touch. “That is _exactly_ what I’m telling you.”

Dean closed the small gap in between them, his breath ticking the shell of Castiel’s ear as he murmured, “Sing to me, my beautiful Siren, my Omega,” the Alpha placed a kiss to Castiel’s throat, “my true mate.”

“Okay,” Castiel whispered meeting his Alpha’s gaze, he cleared his throat before he began his serenade.

“ **I swear to you, I will always be there for you.  
There's nothin' I won't do.  
I promise you, all my life I will live for you.  
We will make it through.**”

Dean swayed as the melodic tone of the Siren’s pleasing tune wrapped around him. He felt fevered, his blood pumping in his ear, and arousal thrumming in his veins.

“ **Forever, we will be.  
Together you and me.   
Mmm, when I hold you, nothin' can compare.   
With all of my heart you know I'll always be...**”

Castiel trailed off, watching his mate stare at his lips in dazed lust. This was the first time the Siren had ever sung to seduce an Alpha, and his inner Omega was preening. He could smell Alpha arousal pouring off Dean in waves as he moved in closer for a kiss.

“ **Right there.** ” The Siren whispered as his eyes fluttered closed and he waited for Dean’s lips to claim his.

A loud bark and Finn forcing himself between the mates broke the spell, but not before Dean’s lips landed on Finn’s cheek. The Alpha’s eyes snapped open at the feel of short wet fur instead of soft supple lips under his.

“Finn!” Dean sputtered as he wiped his mouth with the back of his hand. Castiel chuckled loudly in return as the sea lion snorted and pressed his snout to Dean’s cheek before splashing them both as he swam out deeper into the water.

“That wasn’t exactly the kiss I wanted,” Dean grumbled as he smiled over at his giggling mate. “That song Cas, _WOW_.” He shook his head smiling wider, “The way it made me feel, I can’t even begin to explain it. But I do know one thing, I definitely want you to sing for me again.”

“Anytime you want, Dean,” the Omega whispered shyly as he flitted his fluke, creating small waves. “I’d be honored to sing for you again.”

Dean let out a contented hum as he looked around the shore, sighing softly when he thought about the many nights he spent out here looking for Castiel. 

“You know,” Dean started as he glanced over at his Omega, “last night wasn’t the first time I heard you sing.”

What?” Castiel blurted as he stared at Dean wide-eyed.

“Yeah,” Dean nodded. “I heard you when I first moved in. So I walked down here every night after and sat on the shore collecting shells, hoping to hear, or better yet, see you.”

“I know,” Castiel murmured as he stared down at his lap. “I was over there,” he pointed to a large cluster of rocks, “watching you. I thought you were fascinating. Every night it became harder and harder not to make myself known to you.”

“I’m glad you finally did.” Dean reached over and took his mate’s hand as he shot him a small smirk. “Thought you could have just said hello.”

“I’m truly sor-”

Dean cut him off with a kiss. “No need to apologize. It’s fine.” The Alpha wrapped his arm around his Omega’s shoulder as he asked, “What’s it like, Cas, being a Siren? Did you enjoy singing me to the water? Well, until you realized you were about to kill your true mate.”

Castiel took a deep breath and blew it out slowly as he contemplated how to answer. “Being a Siren is…” he trailed off with a huff, “complex. I love how with a simple song I can comfort and seduce you. I liked singing to you in that way. But, my death song,” Castiel shrugged, “I didn’t enjoy singing it, Dean. I wasn’t comfortable with having someone’s life in my hands.” Castiel glanced over at his mate. “You are a good man, a good Alpha, and I almost killed you.” Shame filled the Siren’s eyes as he whispered, “If you hadn’t been my true mate I would have let you die. And now that I know you, I know you wouldn’t have deserved to meet that kind of fate.”

The Siren shook his head determinedly. “I won’t risk killing an innocent. The only way I will ever sing my death song again is if I know an Alpha is deserving to hear it, like the one that killed my mother.”

“And that’s fine,” Dean whispered comfortingly as he ran his fingers back through his Omega’s hair. “You don’t have to sing your death song if you don’t want to.”

“What will my father think of me?” Castiel sniffled as he lowered his head. “You saw how he took the news about you? He was so angry. I’ve never seen him that mad before, especially towards me.” He looked up into his Alpha’s eyes, his own shining with tears. “Singing our death song proudly has been the way of the Siren for centuries. What do you think my father will say when I tell him I want to denounce those ways?”

“I don’t know,” Dean answered truthfully as he wrapped his arms around his mate, holding him tightly. “But I do know one thing, change isn’t always a bad thing, Cas. Change can be good,” he pressed a gentle kiss to his Omega’s forehead. “Change brought me here, to you.”

Dean held Castiel tightly as they laid back and looked up. They felt Finn flop down by their flukes, the sea lion tired from swimming and playing. The full moon shimmered down, dancing across the water. Thousands of stars as far as the eye could see surrounded the orb of night, and twinkled like diamonds in the inky black sky.

“You ready to head home?” Dean asked as he nuzzled at his mate’s jaw.

“Not just yet,” Castiel cuddled closer in his Alpha’s arms. “Let’s look at the stars a while longer.”

  


  


Dean and Castiel stayed out to the wee morning hours staring at the stars and talking. Talking about Dean’s life on land and Castiel’s in Atlantis. There’d also been more kissing, and slow sensual exploration of each other’s bodies. Castiel was well on his way to stealing second base when Dean convinced him it was time to head back home. As bad as he wanted Castiel, he didn’t want to mate him for the first time there on the beach. 

They returned to Atlantis just as the sun was coming up. Castiel pulled a nervous Dean back to his room. The Alpha paused outside the door and said maybe it wasn’t such a good idea, as much as he wanted to, maybe he should stay in Gabriel’s room instead. Castiel countered by shaking his head and telling him his father already knows they’re true mates, and besides, Gabriel snores. _Loudly_. No way would Dean want to sleep in the same room with him. 

Dean relented, allowing Castiel to drag him into his bedroom and to his nest. As they settled down into the sand the Alpha had grumbled that they had magic so why didn’t they have beds, especially beds with memory foam. And covers, why the hell did they not have covers? Castiel rolled his eyes playfully and explained to him that they didn’t need those things, that they just burrow into the sand and it feels _great_ , especially on their tails, way better than beds or covers ever could.

Pillows though, pillows were something they did have. Dean had sent a silent thanks to the Gods for that. Because there was no way in hell he would have been able to sleep without a pillow. The Alpha gave Castiel a big smile when he handed him a soft plush pillow. And like the muffin at Rowena’s and the food from the banquet, it was water free. 

Magic was fuckin’ awesome.

They burrowed into the sand and Dean pulled Castiel flush against his body. The Omega smiled and pressed a kiss to Dean’s lips. Castiel purred and nuzzled his mate’s jaw before fluttering his eyes at him alluringly. Dean chuckled softly and shook his head, telling his mate his bewitching wiles were not gonna work on him. Castiel pooched his lip out and Dean nipped it, promising him that they would be together soon, once they received his father’s approval. The Omega smiled and whispered his agreement and as he snuggled against Dean’s chest, his heart swelled with love and admiration. His Alpha had a willing Omega but had said no because he wanted to get his father’s blessing, and Castiel respected him for that. With a few more chaste kisses the mates fell asleep tangled together, their tails entwined.

  


“Mmm,” Dean hummed, his eyes still closed as he slowly drifted into consciousness. “Cas,” the Alpha chuckled sleepily as he felt a nuzzle at his jawline. “S’to early, I’m still sleepy.” Dean grunted when he felt weight fall across his chest and tug him in. The Alpha cuddled closer, but at the feel of scratchy fur he quickly realized that it _was not_ Castiel’s arm holding him. His eyes shot open and he was greeted by the site of Finn snuggling against him.

“Finn!” Dean squawked as he moved back, glaring at the sea lion that had wiggled his way between him and Castiel. “Come on, pup, not cool.”

Dean heard a chuckle come from his mate and he sat up higher, quirking a brow at his Omega. “You think it’s funny, Cas?”

“Mm-hm,” Castiel smirked as he scritched behind Finn’s ear. “It’s a _little_ funny.”

Finn darted forward and bumped his snout under Dean’s chin, before licking a sloppy stripe up the Alpha’s cheek. “Eww,” Dean scrunched up his nose as Finn barked happily.

“Awww,” Castiel cooed as he watched on in amusement. “He likes you, Dean.”

“Yeah, yeah,” Dean grumbled, but he reached over and patted the sea lion on the head. Happy with the attention he received Finn shimmied out from the middle of the two mates. He swam over to the window bench and flopped down to curl up and go back to sleep.

“So,” Dean narrowed his eyes at Castiel, “just how long were you gonna let me think that was you cuddling and nuzzling me?”

“I don’t know,” Castiel shrugged with a huge grin. “It was rather hilarious, could have kept me entertained for a while.”

“Come here you,” Dean growled as his arms darted out and gripped the Omega’s hips pulling him in for a good morning kiss. “Gods, you taste divine.” The Alpha rumbled against Castiel’s kiss swollen lips, before nuzzling at his Omega’s mating gland and letting out a soft hum. “You smell so sweet, almost _ripe_.”

”That’s because, well,” Castiel gasped when he felt sharp teeth slide across his throat, “my uh…” he trailed off as he bared his throat fully and his Alpha began to lap at it. “Heat, it’s my heat. I’m in the early stage of it.”

“Gods,” Dean groaned. “I was barely able to resist you before. You in heat,” the Alpha shook his head, “I won’t stand a chance against that kind of temptation.”

“Good,” Castiel purred as he pressed his chest against Dean’s and whispered in his ear. “Because I don’t want you to. I’ve waited long enough for my Alpha. Spent many heats alone, with only my hands to aid me.” The Omega entwined his arms around his mate’s neck, “Not this time though. This time it will be _you_ inside me.”

“Cas,” Dean whined as he flopped back into the nest taking his mate with him. “I have to get your father’s permission first. Show him I’m just as good as that Alpha, Arthur, he’d chosen for you.” Dean side-eyed his mate as he asked, “So what was the deal with you and that Alpha? If you hadn’t met me would you have been happy your father had picked him for you?” 

As the moments of silence ticked by Dean’s heart rate picked up. Had there been something between Castiel and the other Alpha? His father said they’d been close growing up. Did they have a special bond that exceeded friendship? He shivered at the thought of that other Alpha, any other Alpha possibly having touched his true mate, it made his inner Alpha rage.

“Dean,” Castiel whispered, pulling the Alpha out from his internal monologue. Castiel waited until he had Dean’s full attention, the Omega’s shoulders had begun to shake from the laughter he was trying to hold in. “I can smell your jealousy, and trust me there is no need for it. Though,” he smirked impishly as he chuckled at his mate, “I am quite flattered that just thinking about the possibility of me with another Alpha caused such a response from you. However, you have nothing to worry about. I’ve never seen Arthur as anything more than just a friend. He’s so,” the Omega crinkled up his nose, “and I mean what I’m about to say in the nicest possible way, because like I said, he’s my friend. But,” he smiled and wrinkled his nose, “Arthur is so stuffy and boring. He’s always chiding me for being too adventurous and curious. If not for you though, I would have accepted. I would have felt obligated. But I don’t think I truly would have ever been happy with him.” Castiel reached up and cupped his Alpha’s cheek. “Not like I know I’m gonna be happy with you.”

“My Omega,” Dean growled as he pulled his mate on top of him and into a fervent kiss. Castiel keened as his Alpha ran his hands down his shoulders, the dip of his back, and gripped the supple mounds of his butt. “Gods you have a great ass,” Dean murmured against his mate’s lips as he squeezed tighter. “Wait,” the Alpha pulled back and met his mate’s eyes, “is it called an ass?”

“Yes,” Castiel snorted and rolled his eyes. “It may not look like a human one, but it’s still an ass. Now,” the Omega gently thrust down, rubbing his sheath against Dean’s, “less talking, more touching.”

Dean groaned as he felt his cock twitch from beneath its scaled confine. “You’re making it very hard for me—”

“That’s exactly what I want,” Castiel purred as he rutted down again.

“Brat,” Dean clutched his Omega’s ass stilling his movements as he continued. “As I was saying you’re making it very hard for me to be a gentleman.”

“I’m not saying we go all the way,” Castiel ran his hands up his mate’s strong chest. “I want to touch you, I want you to touch me, take pleasure in each other’s bodies.”

“Fuck,” Dean moaned as he let his head sink back into the pillow and he stared up at his wanton mate. “How can I say ‘no’ to that?”

“You can’t,” Castiel whispered as he licked his lips and leaned down to trail kisses along his Alpha’s collarbone.

Dean hummed in pleasure as his hands explored his Omega’s body. “You know, I thought your scales would be slimy and jagged, but they’re not.” The Alpha ran his hands down the sides of his mate’s lithe tail. “They’re smooth, with a texture that reminds me of silk, feels good under my fingertips.”

“Don’t let their softness fool you, our tails are very powerful and solid.” Castiel gasped in reply as he undulated against his mate. “I love yours,” the Omega panted in Dean’s ear as he continued the slow and deliciously torturous rocking movement. “It’s a beautiful shade of emerald, I love how long and strong it looks. _Very sexy_.”

“Damn, Cas,” Dean groaned as he gripped his mate’s ass. “Your tail beats everyone I’ve seen since coming to Atlantis. It’s _amazing_ , the deep obsidian that bleeds into shades of blues I’ve only seen in my dreams. It’s so slender and graceful looking as you move through the water.” He looked up at his mate, Castiel’s cheeks were flushed and his lips parted. Dean met his eyes as he whispered, “Gods you’re beautiful, every inch of you.”

Castiel lunged forward, crashing his lips against Dean's. The Alpha's hand slid down to grasp and massage his mate's ass as he devoured his mouth. Castiel gasped into the kiss when he felt the tingling sensation of his back scales giving way to reveal his most sensitive and intimate place. The Alpha growled against Castiel’s lips as the scent of slick reached his nostrils and his finger met his Omega's slippery puckered entrance.

Dean broke the kiss and gazed into Castiel’s eyes as he asked, “this okay?”

“Yes, Gods yes, please.” Castiel keened, torn between pushing against his Alpha’s finger or down against his sheath.

Dean pressed in, past the tight ring of muscle, moaning at the hot wet heat clenching around his finger. Gods that would feel amazing around his knot. At the mere thought, Dean felt his sheath parting, his cock lengthening, and sliding against Castiel’s scales and lower abdomen.

“Fuck, sweetheart,” Dean panted into Castiel’s mouth as he rutted up, sliding his finger in deeper. “You’re so tight.”

Castiel let out a dirty groan when Dean’s finger grazed that special spot inside him. “There,” the Omega gasped as pure pleasure flowed through him. “Again,” he pleaded as he pushed his ass back, keening when Dean rubbed that spot again. Castiel cried out as the mind blowing stimulation caused his cock to breach his sheath and slid against his Alpha’s.

“Gods, Cas,” Dean’s breath caught at the feel of his Omega’s hardness brushing alongside his. The Alpha dipped a second finger into Castiel’s wetness as he whispered in his mate’s ear, “Take us both in your hand, baby, and make us come.” 

Castiel slipped a hand between their bodies and tentatively grasped their cocks. “I’ve,” he looked down into Dean’s eyes, “I've never done this with someone before.”

“Don't be nervous, let your instincts guide you,” Dean replied, his inner Alpha going wild at the knowledge that he was the first Alpha his Omega had touched in such an intimate way. “That’s it, baby.” Dean groaned as his mate slowly slid his hand up and down their cocks. “Little tighter,” the Alpha urged.

“Like that,” Castiel asked as he fisted them with a stronger grip. He slid his hand up their cocks, running his thumb over the heads toying at Dean’s slit making his Alpha shiver.

“Yeah,” Dean nodded as he curled his fingers inside his mate’s soaked hole. “Just like that sweetheart.”

Feeling braver and more confident, Castiel sped up the motion, stroking them faster and harder. Dean’s cock was thick and throbbing in his fist. The Omega stared down at his mate’s face, at the freckles that dotted his nose and cheeks. He wanted to kiss and count every single one.

“Dean,” Castiel drew in a sharp breath, his rhythm faltering as his mate’s fingertips grazed his prostate. The unexpected touch sent a delicious shiver throughout his body.

“Fuck, I’m so close,” Dean moaned into Castiel’s mouth as he moved his hips at the same flow of his Omega’s hand. 

“Me too,” Castiel purred as he nipped at Dean’s bottom lip.

They slid together slick, hot, and fast as they chased their orgasms. Castiel’s eyes widened when he felt the swell at the base of Dean’s cock. He gave it a curious squeeze on his downward stroke.

“Feel that,” the Alpha rumbled as he scissored his mate’s hole, slick dribbling down his hand. “My knot’s swelling all for you, _my Omega_.”

“Yes, yes, yes,” Castiel cried out as he thrust forward into his fist and back onto his Alpha’s fingers. “Dean! I’m gonna come,” the Omega cried out as slick gushed from him, and his cock pulsed, spilling his come between their bodies.

“Gods,” Dean growled as he felt his mate’s spend hot against his cock. With one final thrust into Castiel’s tight fist he followed his Omega over the edge into bliss, his spend mixing with his mate’s on his stomach. 

Castiel collapsed onto Dean, both of them trying to catch their breath as the Alpha lovingly stroked his fingertips down his mate’s back. The Omega gasped when he felt Dean’s cock jerk and release another load between them. He rose up enough to give Dean a curious look.

“Yeah,” Dean reached up and ran his fingertips along Castiel’s jawline. “It’s gonna do that periodically for about twenty more minutes until my knot goes down.” He waggled his brows, “Just think how that’s gonna feel when I’m tied inside you.”

“I can’t wait,” Castiel purred as he pressed his lips to Dean’s and reached his hand back in between them to massage his Alpha’s knot.

The blissful moment was interrupted by the bedroom door swinging open and Gabriel swimming in, head looking down at the sandwich in his hands. He slammed the door shut behind him with his tail, and before either Dean or Castiel could react, Gabriel’s eyes were on them.

“Ewww, what the fuck!” Gabriel screeched as he spun around and faced the door, dropping his sandwich in the process. “I _did not_ need to see you violating my baby brother, Dean-o.”

“We were just kissing,” Castiel replied as casually as possible.

“Yeah, right,” Gabriel snorted. “I can practically taste the sex in here, and the hand between your bodies, Cassie, I’m sure it’s not scratching Dean-o’s tummy.”

“Maybe you should knock next time.” Dean said with a wink towards his mate, who looked absolutely mortified at being caught like this by his older brother.

“Oh, I definitely will! Once is enough, this is going to be seared into my brain forever!” Gabriel shuddered dramatically.

Castiel let out a sigh at his brother’s theatrics, as he readjusted in Dean’s arms. The pair now lay side by side in the nest, Dean’s chest to Castiel’s back due to fact the Alpha’s knot had not gone down enough for his cock to go back in its sheath. If Gabriel did chance turning around there was no way they wanted him to see that.

“Did you need something Gabriel?” Castiel asked as he stared at his brother’s back.

“As a matter of fact I do, I came to deliver a message. Had no idea I’d get scarred for life in the process,” the Alpha grumbled as he flicked his fluke back and forth. “Dad wants you and Dean to meet him in the throne room.”

“What,” Castiel blurted out as he sat up.

“You heard me right. Dad wants you and Dean to meet him in the throne room. And now that I’ve successfully delivered his message, I’m getting the fuck outta here, it stinks like hot seamonkey sex.” He stared down at his sandwich as he reached for the doorknob, grumbling, “Such a waste. Now I gotta go make a new one, assholes.” With those parting words Gabriel slammed the door shut behind him.

Castiel looked down at his mate with wide eyes full of apprehension. “What do you think he wants?”

“Don’t know,” Dean shrugged as he nodded to Castiel’s nestside table where the vial Rowena gave them to cover the other’s scent lay. “Should we put that on?”

“No,” Castiel shook his head. “Father knows you’re my true mate and I’m not hiding it from any one.”

“Okay then,” Dean replied as he pushed out of the nest, gripping his mate’s hand and pulling him up too. “Let’s not keep him waiting.”

  


  


Dean let out a deep breath riddled with anxiety. Castiel clutched his hand like a lifeline as they entered the throne room. King Triton looked even more intimidating than he had last night at the banquet, watching them intensely as they swam further into the room.

Dean was blinded by the jewel encrusted throne. Some of the jewels that adorned it he'd never seen before, so, he assumed they must be sea based. His eyes roamed over the grand room and then to the imposing man before them. His Majesty had a hard grip on his trident. Alone the instrument was frightening enough, but in the grip of a glowering spurned father, it was more than frightening. It was downright petrifying.

Dean felt His Majesty's eyes boring into him as he and Cas approached the throne. As if the man wasn't imposing enough, and as if the marble and gold throne room wasn't intimidating enough, the throne was elevated on a stage seven steps up from the floor. It forced you to look up, and Dean already felt small in the vastness of the ocean. Now, he felt like an ant at the bottom of a slide.

Castiel cleared his throat as he gazed up at the father. “You wanted to speak with us?”

“I did,” Triton nodded as he stared down at the pair. The poor Alpha, Dean, looked as though he’s about to keel over in fear. 

He loosened his grip on his trident and folded his hands in his lap, hoping that would settle the young Alpha’s nerves. “First, I wanted to apologize for my outburst yesterday after you told me about Dean, Castiel. I could have handled it better.” 

“I’m sorry for the hurtful things I said,” Castiel whispered as he flicked his fluke back and forth apprehensively.” 

“It’s fine Castiel. I needed to hear those things, nothing you said was untrue.” Triton sighed as he relaxed against the cushioned high-backed throne. “Now that I’ve had time to regain my composure, and think over all that was said yesterday, I’m ready to talk to you, both, like civilized adults, and not down to you as I did before. But first,” he held up his finger and pointed down at his son. “I want to know why you didn’t just come to me before the banquet, and tell me what had happened with your Rite and with Dean. Why keep it from me?” Triton shrugged, the sadness clear in his eyes, even from the distance the elevated platform created. “Why lie to me, Castiel?”

“I was going to tell you, father, I swear I was.” Castiel babbled as he leaned against his mate, the two pressed together shoulder to shoulder. “It’s just, I just,” the Omega sighed as he stared down at the shimmering floors. “I wanted you to be proud of me, even if it was only going to be for a few hours.”

“Castiel, look at me,” Triton gently urged, waiting until his son’s eyes met his before he continued. “I will _always_ be proud of you, no matter what. And if you didn’t already know that,” Triton shook his head sadly, “then I have failed you as a father.”

“You have never failed me. But I, I have failed the whole of Atlantis, as a Siren.” Castiel whispered, as he looked over to his Alpha drawing courage from his touch, from him just being here by his side. “Could you still be proud of your Siren son if he told you he didn’t want to sing his death song? If he told you he’d been having doubts about singing for quite some time now. That he is worried that he will sing to Alphas that don’t deserve to meet that kind of fate. Alpha’s like Dean.” Castiel gave his mate’s hand a squeeze as he glanced over at him again, this time with a small smile before turning his attention back to his father. “Could you honestly still be proud of me?”

“You are so much like your mother.” Triton chuckled as he smiled faintly. “She had the same doubts too, you know.” 

“She did?” Castiel asked in a hushed tone as he stared up at his father.

“Yes, she did,” Triton nodded, a faraway look on his face as he thought about his beloved wife. “My dear Cordelia rarely sang her death song, and when she did it was only to those who she knew for sure were deserving. But you were so young when she passed...” Triton sighed as he shifted on his throne, “I can imagine you don’t remember, do you?”

“I had no idea,” Castiel whispered as he shook his head. “I thought I was the only Siren that ever had these doubts, I thought something was wrong with me.” Tears welled up in his eyes as he thought of his mother, and how she’d had the same reservations as him. “So I’m _not_ the only one that has had doubts.”

“No, Castiel, you’re not.” Triton gave his son a warm smile as he continued, “And I loved your mother dearly. Her reservations meant nothing to me. I supported her in what she wanted. Just as I love you, and will support you. If you don’t want to sing, don’t sing.” He leaned forward and met his son’s earnest gaze. “You are not a failure as a Siren, and you, in no way, have let Atlantis down by being true to yourself.” He looked truly shamed as he whispered, “and I’m so very sorry I told you otherwise yesterday.”

“Thank you, father.” Castiel replied, his voice hitching as he held back tears of relief. His father accepted him as he was. Now, would he also be willing to accept Dean as his mate?

Castiel glanced over at Dean. The Alpha was looking at him with such adoration the Omega couldn’t help but to press in closer. Dean wrapped his arm around his mate’s waist and pulled him flush against his side. Castiel could scent pride on his Alpha as the two of them stared intently into each other’s eyes. Dean was proud of him, proud that he told his father how he felt, who he really was.

“Well, Castiel,” Triton cleared his throat drawing his son’s attention back to him. “Now that you have cleared that weight from your chest, and you now know I will love and be proud of you no matter what. I want to talk about you and Dean.”

“Okay,” Castiel nodded, as Dean shift nervously beside him. “What would you like to know?”

Triton regarded the pair for a moment before he spoke. “Tell me how you knew Dean was your true mate.”

“That’s easy,” Castiel grinned widely as he twined his tail around Dean’s, trying to soothe his anxiety. “I was instantly drawn to him when I saw him, the way he moved, his smile, everything about him intrigued me. I watched him from afar for over a month, wanting so much to sing to him. Then when I finally did serenade him, and he followed my voice to the sea, the wind changed its course. His scent reached me, and it was like coming home.” His smile turned shy as he met Dean’s eyes. “Then there was our first kiss, the way it made me _feel_. Every time he touches me my inner Siren is screaming at me to sing him songs of comfort and seduction.”

“Alright,” Triton nodded to his son before he turned his head, quirking a brow as he peered at Dean. The Alpha gulped as he was pinned by a steely gaze. Dean just knew he was mulling over his son’s answer. Probably focusing on the parts Castiel had divulged about the kissing and touching. It took everything in Dean not to shirk away from that look. “Dean,” Triton finally addressed him, “if you could only use one sentence to explain to me what Castiel means to you, what would it be?”

Dean didn’t even need to think, he knew the answer immediately. He straightened up and met Triton’s eyes as he responded with certainty. “Cas is the ocean, and I’m desperate to drown.”

“I had already planned on giving my blessing,” Triton admitted with a small smirk. “But after that answer, Dean,” he shook his head, his smirk turning into a sentimental smile, “It reminded me so much of the way I felt for my Cordelia, that I know I’ve made the right choice in letting you two bond.”

“I… with how angry you were last night, not that I’m complaining, but,” Castiel looked his father squarely in the eyes, his own filled with curiosity as he asked, “what made you change your mind?”

“Some of the things you said to me last night got me thinking about your mother,” Triton admitted with a sigh. Castiel opened his mouth and Triton held up his hand cutting him off. “Don’t even try and apologize again, I told you I needed to hear those things. Anyway,” he lowered his arm as he continued, “last night after I blew up, I went to my chambers. After pacing the room for over an hour, out of the corner of my eye I saw your mother’s old jewelry box, and our last moments together flooded my mind.” He licked his lips as he looked down on Dean and Castiel. The pair was still wrapped up in each other. “Before she passed she told me to always trust in our sons—that they are wise, so support them in the choices they make. And, above all, make sure they live happy lives. So I knew if I forbade you from seeing Dean, it would take all that away from you, and I would have never been able to forgive myself. So, Castiel,” he nodded towards his son, “I trust your judgement that Dean is a good man.” 

“Thank you,” Castiel grinned up at his father, his eyes filled with happiness and appreciation. “Thank you so much, father.”

“Sire,” Dean began as he untangled himself from his Omega and moved closer to the steps. “Thank you for your blessing,” he bowed before looking back up into Triton’s eyes and vowed, “I will prove to you that you’ve made the right choice. I will be the best Alpha for Castiel.”

“Just call me Triton, Dean. And I have no doubt that you will be.” He darted from the throne and swam down to the pair, pausing in front of them. Triton turned to the younger Alpha. “Dean, if you choose to mate Castiel you need to know something Rowena informed me of this morning. Once you bite Castiel and his blood enters your mouth sealing your bond you will become a Merman for good. No need for,” Triton pointed to the necklace snug around his throat, “that anymore.”

“Okay,” Dean nodded, his eyes never leaving the elder Alpha’s face.

“Do you fully comprehend what that that means for you?” Triton asked as he furrowed his brows. “You will be giving up your life on land, you will be separated from your land family, only being able to see them on the shore. But that’s not all.” Triton shook his head as he held Dean’s gaze. “As a Mer you will age differently, you will live for hundreds of years. You will watch everyone you love grow old and die, can you handle that?”

Triton then looked to his son, “Will you be able to respect whatever he chooses?”

Dean and Castiel glanced at each other then back to the elder Alpha before both opening their mouths to answer, but they were cut off by Triton. “Don’t answer so quickly, think on it, both of you. And Dean, while you are ruminating over everything you should know when Rowena came to me this morning to give me that piece of information about your bonding with Castiel, she also informed me that she has an antidote that would reverse the effects of the spell and return you to your human form again.”

Triton placed a hand on both Dean’s and Castiel’s shoulders, giving each a comforting squeeze. “I believe I have given you both much to think on.” He pulled Castiel into a hug then held out his hand for Dean to shake. Triton sighed as he shook his head, “Now, I must go find Crowley and tell him the arrangement with Arthur is null due to Castiel finding his true mate.”

The pair watched as Triton left the room in search of the Sea Enchanter. The Omega reached out and twined his fingers with Dean’s before he broke the silence. “We have a lot of things to discuss.” He gave his Alpha’s hand a firm squeeze. “Come on, Dean, I'll take you to one of my favorite places in all of Atlantis, the place where I like to go think.” 

Dean nodded as he followed Castiel. He could see the tension in the set of his mate’s shoulders. He could smell worry and apprehension rolling off of him. Dean couldn’t help but to shake his head slightly, didn’t his mate already know that this would be the easiest choice Dean had made in his life. He had no reservations, no fears, sure he would miss his family, but he knew if he left Cas, he would never be the same. He would always have a hole in his chest where his heart once was. 

This is his life now, and as unexpected as it is, he’s happy. Atlantis is his new home, and now that he had Triton’s blessing, Castiel would soon _officially_ be his mate. 

He had no doubts. 

None at all.

**Notes for the Chapter:**

> Hope you enjoyed the chapter!
> 
> Oh and the song Cas sang to Dean is I’ll Always Be Right There by Bryan Adams.
> 
> [ _**Graphics Masterpost created by ZephyrChrysalis here!**_ ](https://archiveofourown.org/works/15728604/chapters/36566784)


	6. Chapter 6

**Notes for the Chapter:**

> Big thanks to Ani-make-me-girl for beta’ing this chapter, and zephyrchrysalis for Alpha reading and providing art.
> 
> This chapter is another long one!
> 
> Enjoy! :)

  


  


**“What would an ocean be**

**without a monster lurking in the dark?**

**It would be like sleep without dreams.”**

**Werner Herzog**

“Amazing,” Dean whispered as he stared at the gazebo in awe. Was everything in Atlantis ethereally beautiful? His eyes roamed over the six large gold columns, spread out perfectly to form a cylinder. The colonnades were dotted with a variety of precious gems, and seaweed twined up them in a manner that reminded Dean of the way Bobby wrapped tinsel around his porch posts at Christmas time. As the Alpha’s gaze followed the trail of seaweed up the pillars his eyes landed on the stunning Larimar Stone dome. It was a whirling galaxy of spiraling blues and greens, mixed with white. It was mesmerizing. 

“This is where you like you come to think?” Dean asked as he followed his mate into the gazebo. 

“It is,” Castiel nodded to his Alpha as they swam over to the large marbled bench and sat down. “I’ve always loved the courtyard it has such a wonderful view of Atlantis.” A few younglings darted by quickly, laughing and chasing after a bale of frolicsome sea turtles. Castiel smiled over at Dean before turning his attention back to the chase, “I also enjoy watching the younglings play.” 

“Younglings?” Dean asked, his brows dipped in confusion.

“Children,” Castiel clarified as he shifted on the bench, moving closer to his mate. “You call them children on land.”

“Ohhhh,” Dean whispered softly as he watched the younglings. He chuckled softly as he watched a little girl grip one of the larger sea turtle’s hind flippers. He watched as the aquatic animal zipped and zagged, pulling her along for a ride. 

Dean’s eyes caught on a large bust of a mermaid that looked as if it had once served as a ship's figurehead. The stone mermaid was surrounded by a garden of beautiful pink and purple sea anemones, swaying gracefully with the movement of the water. Her arm was stretched out in front of her, holding a lantern, as if she’d once guided a many of voyages. She stared heavenward, her hair in ringlets hanging over her shoulders and covering her breasts.

Castiel noticed his mate’s keen gaze on the figure. “Merfolk are scavengers, they loot sunken ships and use what they can for decorations and such, then barter with the goods they don’t need or want.”

“Very practical.” Dean acknowledged with a nod. An inquisitive look spread across the Alpha’s face as he looked up then over to his mate. “Hey, Cas, what would happen if a ship sunk and fell on Atlantis?”

“Absolutely nothing,” Castiel replied with a small shrug. At Dean’s perplexed gaze he continued. “There’s a magical dome over Atlantis that protects it from falling debris. If something touches it the sea will swiftly move it a safe distance away.”

Castiel stared at his Alpha as he studied everything around him with such intensity and curiosity. “Dean,” he murmured softly as his fingers nervously clutched at one of the shells on the necklace his aunt had given him to wear. “We have stalled for as long as we can. We really need to discuss…” Castiel trailed off with a sigh, squeezing the shell harder. “We need to discuss a lot of things.”

  


  


“Cas,” Dean whispered as he reached up and pried his mate’s hand from the shell. He held it in his own as he rubbed his finger along the indentation left behind by the shell he’d clasped so hard. “Not that this necklace doesn’t look good on you, but why are you still wearing it?” Dean’s eyes flitted over the brown spotted Tiger Puka shell choker. “Your father knows the truth now.”

“It’s silly,” Castiel shook his head as he chuckled quietly.

“I’m sure it’s not.” Dean tentatively cupped his Omega’s jaw, urging him to meet his eyes. “Tell me, please?”

“Even though father knows, I’ve worn my mother’s necklace for so long now,” Castiel ran his hand up Dean’s chest until he reached the necklace. The Omega caressed the pearl between his thumb and forefinger as he finished explaining, “I feel bare without it.”

“I understand what you mean.” Dean mumbled as he took his palm from his mate’s cheek and covered Castiel’s hand that held the pearl. “Once, my brother gave me this amulet, and I wore it forever, then one day it broke and was just gone, I couldn’t find it anywhere. Felt naked without it for the longest time. So, I’m sorry that—”

“Don’t be sorry,” Castiel cut his mate off as he twined their fingers together and dropped their joined hands to his lap. “I’m honored it’s you. If not me, I can’t think of a better person than _you_ to wear her necklace. It’s yours now, and even if you chose to leave Atlantis,” Castiel shook his head when Dean opened his mouth to speak, silencing him. “I want you to keep it to remember me.”

“Cas, I’m not going anywhere.” Dean replied with such determination as he stared into his Omega’s baby blues. “I’m not leaving Atlantis. I’m not leaving _my true mate_.”

“You can’t just make such a massive decision without even thinking about it, Dean.” Castiel blew out a deep breath, “what about Baby? Last night you told me all about how you would take her out on nice sunny days, how you loved hopping in her and riding around for hours, no destination in mind just you, her and the open road.” Cas held his mate’s gaze, “You told me how much you loved working on her, keeping her in tip top shape. You do realize,” Castiel’s eyes searched Dean’s, “that if you stay here with me that’s something you will _never_ be able to do again, right?”

“Yeah, I do,” Dean nodded as he met Castiel’s eyes. “And I can live with that. I’ll give Baby to Sammy, he’ll take good care of her for me.”

“Then what about Sam?” Castiel whispered as he ran his fingers back through his Alpha’s hair. “He and Jess have just started a life together. Don’t you want to be there to witness all their joys, like birthdays and anniversaries? When they have children, are you going to be okay missing all that? And Bobby,” Castiel continued, “what about him? You said he was getting up in age and that you wished you could see him more. Living down here that won’t be possible.”

“They can visit Nassau.” Dean shrugged as he leaned into his Omega’s touch. “They can stay in my cottage when they come and we can go to the shore and spend time with them.”

“Would you truly be happy with only a few hours here and there throughout their remaining years?” Castiel asked softly. “Because remember, Dean, if you choose this life you will age differently, you will watch them all die.” The Omega’s fingers gently scratched Dean’s scalp as he pressed on before his mate had a chance to answer. “What about your home? I know you said last night that you owned your cottage outright, but what about property taxes? I once read in the Atlantian library that you are required to pay taxes on the land you own. How are you going to do that from Atlantis?”

“Jesus, Cas,” Dean huffed a shaky laugh. “It damn near sounds like you are trying to talk me out of choosing a life in Atlantis with you.”

“No,” Castiel shook his head, “that’s not it at all. But as much as I want you here with me for the rest of our lives, you can’t make this life changing declaration without considering every aspect of how your entire world is going to change. You have to be certain _this is what you want, that _I’m__ what you want.” 

Castiel leaned forward and rested his forehead against Dean’s as he whispered, “I don’t want to look in your eyes years down the road and see regret in them. Regret that you stayed with me. So, please,” he pressed a kiss to Dean’s lips, “take some time to weigh your choices.” 

“I will, I promise.” Dean murmured as he nuzzled at his mate’s throat, humming when the ripe sweet scent of Omega heat permeated his nostrils. “Smell so good, like love and mate and home,” Dean slurred, lust drunk on hormones. “So ripe and ready for me.”

“I would suppose so,” Castiel chuckled softly as pulled back and met his Alpha’s gaze. “I’m hours away from being in full blown heat. Which is why I’m going to go, and you are going to stay here and spend some time thinking.” 

Dean looked like he was about to protest but Castiel shook his head firmly. “I don’t want my pheromones to sway your decision. I’ll wait for you in my room for your answer.” The Omega cupped his mate’s cheeks and kissed him, softly but passionately, pouring all his adoration into this one kiss. When Castiel pulled back breathlessly he trailed his thumb across Dean’s bottom lip with a small smile before turning and swimming towards the castle. As he reached the gates, he spun around and called out, “No matter what you choose I will understand and respect your decision.”

Dean sighed as he watched his mate until he disappeared completely beyond the golden gateway. He had a hell of a lot to think about and no clue where to start. Dean shifted on the bench, blowing out a deep breath as he glanced down, jumping when he noticed a crab scuttling towards him on the bench. He held out his palm and the tiny crab crawled into it.

Dean brought his hand to his face, snorting as he muttered to the crab, “This is some straight up Disney shit right here. You gonna start singing?” Unimpressed with the Alpha the tiny crustacean pinched Dean’s forefinger. 

“Ouch!” Dean yelped as he sat the crab down and glared at it. “Not cool, Sebastian, you were way nicer to that Ariel chick.” 

He watched as the crab bustled away before looking up at the castle. His eyes landed on Castiel’s window and he couldn’t fight the smile that spread across his face knowing his mate was there, was waiting for him. 

Deep down he understood where Castiel was coming from and why he wanted Dean to be absolutely sure. If roles had been reversed Dean was positive he’d have pointed out certain things to him and urged Castiel to really think things through too. Dean couldn’t imagine spending years with Cas on land thinking they were happy only to one day see regrets in his Omega’s eyes. It would break his heart knowing it all could have been avoided, if Castiel had just taken the time to look at the bigger picture. It would shatter him completely.

So that’s what he needed to do. He needed to look at the bigger picture. Not just kill time until he thinks a suitable amount of time has passed before returning to Cas with his decision. He already knew the words he wanted to say were, ‘I chose you’. But all the things Castiel brought up... If he stayed here there would be no more sunny day drives with Baby. He wouldn’t see Sam and Bobby as often, his life would be completely different. He really did need to take this time to weigh all the pros and cons of staying in Atlantis versus going back on land. 

Dean glanced around, taking in Atlantis and all its wonder and for the first time it made him wonder, too. Wonder if Atlantis had a darker side. Everything here seemed so damn perfect. Was it really as it seemed? Or out there in the dark of the ocean were there hidden unpleasantries, or criminal parts of this society? Rival clans maybe? Everything good always had a little bad in it too. At least that was his experience. But, so far, Atlantis didn’t seem to follow suit. 

His eyes fell on the garden of sea anemones and the bust of the Mermaid once more and he pushed off the bench and flitted towards it. He passed a group of younglings who were playing what looked to be tag and he couldn’t help but smile. Atlantis held a lot of love that was for sure. It would be a great place to raise a family. 

Definitely a point for the pros column the Alpha thought as he settled down in the sand by the large garden, his fingers immediately digging into the sand to search for shells. He found the act calming, it soothed his restless nerves, allowed his mind to clear so he could think. And he had a lot of that to do.

  


  


“Well, what do we have here?” Dean glanced up to see Rowena staring down at him, smirking at the large pile of shells he’d collected in his lap. Dean had a brief moment to wonder just how long he’d been sitting there thinking before Rowena spoke again. “Mind if I join you?” She motioned to the spot beside him.

“Not at all.” Dean smiled and patted the sand invitingly.

“Sooooo,” Rowena drawled as she settled down next to the Alpha, placing her small black clutch between them. 

Dean quirked a brow at her, “Mermaids carry purses?”

“Yes,” Rowena rolled her eyes. “Not like these tails come with pockets, and like land ladies we Mermaidens have them to carry our essentials.”

“Of course,” Dean snorted as he placed another Angel Wing shell on his lap. “And just what kind of _essentials_ do you carry around?”

“Don’t you know it’s rude to question a lady on what she has in her purse?” Rowena replied primly. She glanced up at Dean, her brow rose slightly, “What are you doing out here all alone?”

“Thinking,” Dean sighed as his fingers dug deeper into the sand.

“Ahh,” Rowena hummed as she leaned back on her hands. “I take it you and Castiel met with Triton and he explained everything to you.”

“We did, and he did.” Dean mumbled as he tossed a broken shell to the side. “And then Castiel and I talked and he wanted me to take some time by myself to really mull everything over.”

“Makes sense,” Rowena nodded as she watched Dean’s fingers deftly work through the sand and pull out a Auger shell. “What are you gonna do with all those?” Rowena asked as she nodded towards the pile of shells in his lap.

“Dunno,” Dean shrugged as cleaned the sand from inside the Auger shell. “Haven’t really thought about it, been busy ruminating on life changing decisions. The shell hunting just calms me and clears my head.”

“I’ve got an idea,” Rowena grinned as she sat up and reached for her clutch. Dean watched as she dug through it, brows furrowed, and on a mission. “Ah-hah!” She crowed as she pulled out a thin bright green braided strip of seaweed and a small silver hand push drill. “No sense in letting all that hard work and those pretty shells go to waste.” She handed him the seaweed and tool with a smirk.

Dean glanced at the stuff in his hand then back to Rowena, an expression of confusion maring his features. “Wha—”

“A necklace,” Rowena sighed and looked at Dean as if he were the densest Alpha in all of Atlantis. “Make Castiel a necklace to replace the one that now resides around your throat.”

“You think...” Dean trailed off as his gaze darted to the pile of shells then back to Rowena’s smirking features. “You think Cas would like that?”

“Of course,” Rowena rolled her eyes and crossed her arms over her chest. “I wouldn’t have suggested it otherwise. Now,” she nodded towards the small drill still clutched in his hand. “Why don’t you start making the holes in the shells so you can thread them, and while you’re doing that we can have a nice chat about what’s on your mind.”

“Okay,” Dean gave her a grateful smile as he picked through the shells putting his favorites in between him and Rowena. Not wanting the seaweed strip to get misplaced he laid it with the shells until he was ready to use it. “So, Cas wants me to have zero doubts when I come to my decision.”

“Do you still?” Rowena picked up a shell and twisted it between her fingers, admiring its beauty. “Have doubts, that is.”

“No,” Dean smiled brightly at her as he shook his head, eyes holding nothing but the truth. “And damn, did he ever try and make it hard on me.” Dean held the Angel Wing shell in his hand and gently started to twist the drill making a small hole in it. “I understand why he brought up all the obstacles he did, but when I actually sat and thought about them, I came up with solutions.”

“Such as,” Rowena asked as she passed him a Periwinkle shell when he’d finished with the Angel Wing one.

“My car.” Dean replied as he took the shell and started working on it. “I love my car, but I can see myself giving it up for my true mate. I can’t, however, see myself giving up Cas for a hunk of metal. My car, no matter how important it is to me, will never be as important as my Omega.”

“I see,” Rowena hummed as she watched Dean methodically work his way through the pile of shells, drilling tiny holes in each of them. “What else?”

“My brother Sam, his wife Jess, and my uncle Bobby.” Dean glanced over at Rowena as he picked up the braided seaweed strip. “Cas is worried I will regret giving up missing out on their lives. But,” Dean smiled as he started threading shells on the seaweed. “I got to thinking, Sam, Jess, and Bobby would want me to be happy. And if Cas is what makes me happy, they’d all tell me to go for it. They’d rather see me genuinely happy and see me less, than see me every day and miserable. They can visit Nassau, stay in my cottage, and we can visit them on the shore. And you know what?” He looked over to make sure he had Rowena’s attention. “I’m completely fine with that arrangement. I can’t think of a life without Cas being mine. It feels like a fate worse than death, now that I have scented him, kissed him, touched him. My Gods this morn—”

“Please, you are getting off track.” Rowena sputtered as she placed her hand over Dean’s mouth silencing him. “I don’t want any details.” The Alpha snorted a laugh and rolled his eyes, nodding so she’d remove her hand. “Moving along.” She urged as she handed him a Sparse Dove shell.

“After that Cas brought up the fact that even though I own my home outright, I would still have to pay property taxes on it. He asked how the hell I could do that from Atlantis. Now that one, I had to think about.” Dean gnawed on his bottom lip as he worked an Angel Wing shell onto the seaweed, grinning when he realized it was half way finished. He placed it in his lap and looked back up at Rowena. “Then it hit me, before I moved here I had Sam added onto my savings and banking account. I made a lot from selling my company and from good investments. He and Jess are just getting started in their life together so I added him to it in case they ever needed anything. So,” Dean shrugged with another grin, “he can just mail in the payments when they are due.”

“Sounds like you have everything all figured out.” Rowena whispered as she dug her fluke into the sand.

“I do,” Dean nodded. “I want to be with Cas, and I’m willing to do _anything_ to make that possible.” The Alpha picked up the half-finished necklace as furrowed his brows as he gazed at it.

“What?” Rowena asked when she noticed the look of dissatisfaction on his face.

“I wish I had something other than a shell to put in the middle.” Dean muttered as he reached up and caressed the pearl on his necklace. “Cas deserves something as breathtaking as he is.” 

“I believe I may have something you can use.” Rowena smiled as she picked up her clutch and dug through it again. Her smile widened when she found what she’d been looking for. “Here!” She held out her hand, waiting for Dean to open his. When he did, she dropped a briolette shaped malachite stone on his palm.

“It’s perfect,” Dean mumbled as he studied the intense rich green with beautiful banded masses. “But I can’t,” the Alpha held out his hand to give it back. “It’s yours.”

“No,” Rowena shook her head and gently pushed his hand away. “That stone, it’s malachite, and was always meant for you. I know that now.” At Dean’s utterly perplexed look Rowena continued. “Cordelia, Castiel’s mother, gave me that stone on her deathbed. She told me to hold on to it until the right time, and that I’d know when it came.” She huffed a laugh and sighed fondly. “I may have been the one blessed with magic, but, I think my sister was psychic.” Rowena gave Dean a warm smile and patted his hand that held the stone. “I think she knew about you all along.” 

“Thank you.” Dean whispered as he carefully drilled through the gem before sliding it to the center, and placing an Angel Wing shell on the other side of it. He ran his finger down the jewel, smiling at the pair of Angel Wings encompassing it.

“You are more than welcome,” Rowena grinned as she watched Dean methodically pick out shells to pair with the completed side of the necklace. “Would you like to know what malachite stone stands for here in Atlantis?”

“Yes,” Dean bobbed his head but didn’t look up as he was threading an Auger shell.

“The malachite stone,” Rowena began as she shifted in the sand, getting comfortable. “It means love, happiness, and communication, all the key elements to a successful mateship.”

“Then it really is perfect,” Dean looked up, meeting Rowena’s eyes. “Because I plan on making Castiel the happiest Omega in all of Atlantis.”

Rowena studied the Alpha closely for a moment before muttering, “You really do love my nephew, don’t you?”

“I would hope that was pretty damn obvious.” Dean snorted and shook his head. “I’m giving up my life on land without a single doubt that it’s the right thing for me to do. So yeah,” Dean grinned and went back to work on the necklace. “I really do love your nephew.”

“Then there’s no need to choose.” Rowena leaned forward and propped her elbow on her tail. “I can give you and Castiel the best of both worlds.”

“What are you talking about?” Dean asked as he quirked a brow and glanced over at her.

“I can make you and Castiel a necklace much like the one I made for my sister, except, instead of holding a wish,” Rowena reached over and tapped the pearl with her crimson finger nail, “it will read your intentions. When you go to the surface with the want in your heart to be on land your tail will turn to legs, and when you enter the sea wanting to return home to Atlantis, legs will become tail once more.” 

“You can,” Dean’s eyes widened in shock and he licked his lips as he stared at the Sea Enchantress in awe. “You can do that?”

“Of course,” Rowena rolled her eyes and waved her hand with a flourish. “Piece of cake. I told Triton all about it this morning when I delivered the other news. But,” she smirked as she shrugged nonchalantly, “He wanted you to make your decision without that tidbit of information. He wanted you to fully understand what you could be giving up without knowing that magics could give it back to you.” 

“I’m in no matter what. With or without magical land navigating necklaces,” Dean assured her with a warm smile. “Do you think Cas would like that, though? Being on land—” the Alpha trailed off as he remembered their conversation from the night before. How Castiel had told him he always wanted to travel the world. “He did say he wa—”

Rowena’s laughter drew him from his musings and he glanced over to her. “Oh, knowing my nephew he will most definitely want that opportunity. He’s always been so curious.” 

“The necklaces,” Dean mumbled as he picked up a Shark's Eye Moon shell. “Would they have to be new ones or could you spell the one I already have and this one I’m making for Cas?”

She smiled softly, “I can bewitch any necklace you two want. But,” her features hardened to a look of seriousness. “If you two choose that route you have to promise me that you will bring Castiel home often, that you won’t let him get caught up in the wonders of land living and forget about _home_.”

“I swear,” Dean threaded the last shell and laid the completed necklace on his lap as he met Rowena’s eyes. “Even though I’ve only been here for a couple days, Atlantis feels more like home than anywhere ever has. And deep down I know, one day after showing Castiel all the marvels of being on land, we will return to Atlantis for good.” A smile painted Dean’s lips as he whispered, “To raise our younglings. 

“Ohhhh, younglings!” Rowena cooed at the prospect of grand nieces and nephews to spoil. “Twins run in our family you know. Cordelia and I were fraternal twins.” She grinned at the finished necklace and rooted around her purse pulling out a set of necklace clasps. She scooped up the drill and snapped her purse closed.

“Here,” Rowena held out her hand. “Let me see the necklace so I can add the clasps.” Dean gently handed it over to her and watched as she added the clench. After it was completed she held the necklace in her hands and murmured a few words.

Dean quirked a brow. “What was that?”

“Just a wee spell.” She smirked as she handed the necklace back. “Now it’s indestructible, like the one around your neck.”

Dean snorted as he twisted the necklace in his hand. “You do that to all your jewelry?”

“Nah,” Rowena shook her head before grinning at Dean. “Just the _really important_ trinkets.”

“You think he’ll like it?” Dean asked as he examined his handy work.

“He will love it. That necklace is fit for a prince. Well,” she grinned widely at him. “What are waiting for?” Rowena shoved at his shoulder mirthfully. “Go give my nephew that necklace, and ask him to accept that gift, and you as his Alpha.”

“Thank you,” Dean leaned over and hugged Rowena. “For everything,” he whispered.

“Don’t mention it,” Rowena smirked as Dean rose and swam towards the gates. “Oh and Dean,” she waited until he turned. 

“You two make the most of Castiel’s heat! Get started on some younglings for Auntie Ro to spoil rotten.” 

Dean flushed scarlet as he turned and swam faster towards the castle. He could hear Rowena’s laughter following him until he was well past the gates.

He swam quickly down the halls, passing guards and staff, praying he correctly remembered the path Castiel had showed him the night before. When he made a left at the end of a long corridor, he grinned. This was the hallway that lead to Castiel’s room. He sped up, flicking his fluke faster until he reached his Omega’s door and flung it open.

“Cas,” Dean called out.

The room was empty. 

Dean swam further into the bedroom. His Alpha senses immediately on high alert when Finn started barking hysterically as he approached the nest. The scent of his mate’s fear permeated his nostrils and the sea lion nudged at his hip as he whined. Dean placed the necklace he’d made for Castiel on the nestside table, and his eyes fell down to the sand.

  


  


Tiger Puka shells were scattered everywhere! 

Dean dipped down and picked one up rubbing it between his thumb and forefinger. Castiel’s necklace was torn apart and he felt his mate’s fear all the stronger. The Alpha’s heart began to race as he looked frantically around the room for any kind of clue that could help him figure out what happened to his Omega.

Nothing.

There was nothing except the smell of Castiel’s fear, his broken necklace, and Finn in hysterics.

One thing was for sure, Dean got his answer to the question he’d asked himself earlier… 

Atlantis did have a darker side, and wherever it was, it had his mate.

“Dean-o.” The Alpha spun around to see Gabriel leaning against the door jamb. “Just checking to see if you and Cassie are gonna be banging like sea monkeys through his heat. Cause if so,” Gabriel shivered dramatically, “I’m moving to another room! _I do not_ wanna year that shit!”

“Not now Gabe,” Dean hissed as he ran his hands back through his hair. “Something is wrong. Finn is freaking out and Cas is gone!”

“Dude,” Gabriel cautioned gently not wanting to upset the riled up Alpha more. “That sea lion is so damn dramatic. Cassie probably went for a swim or to get something to eat.”

“No,” Dean shook his head. “His heat is starting, he told me he would come back here and wait for me. And look,” Dean pointed down to the scattered shells. 

Gabriel swam further into the room and examined the fragmented necklace. “Maybe he accidentally broke it.”

“Take a deep breath, Gabe.” Dean crossed his arms over his chest, trying to settle his inner Alpha. “What do you smell?”

Gabriel scented the air, his eyes widened as he gasped, “Fear! Cassie was afraid.” He turned towards the door and bellowed “Inias!” The Alpha’s waited until a dark haired guard swam into view.

“My Prince,” Inias bowed and waited further instructions.

Gabriel cleared his throat. “Go to the throne room tell His Majesty that Dean and I need to speak to him in Castiel’s room, and tell him it’s urgent.”

“Yes, My Prince,” Inias replied before spinning around and flitting away quickly.

Gabriel reached over and gripped Dean’s arm, giving it a gentle squeeze. “Everything will be fine, Dean. Father will know what to do.”

Dean couldn’t speak, he gave a weak nod in return as he scritched behind Finn’s ear, trying to calm him. Dean’s mind racing with nefarious scenarios of where and what could be happening to his mate. His inner Alpha paced, clawing just underneath his skin. Just one clue, that’s all he needed. One clue to his mate’s whereabouts. He needed to hold Castiel, scent him, take care of him. But first he had to find his Omega. Find him and make whoever had him pay, with their blood.

Triton sped into the room moments later and stared down at the younger Alphas. “This better be important.”

“It is, father.” Gabriel nodded and met Triton’s eyes. “Castiel is missing.”

Triton paced his son’s room as Dean relayed every single detail to him. From the moment Castiel had left him in the courtyard to think, to when Dean found his mate’s broken necklace, and the smell of his fear thick in his bedroom. Once His Majesty had thoroughly searched Castiel’s room himself, he immediately called for all guards to scour the castle and the grounds for his son. 

Dean had very little faith that they’d actually find him. And from the anxious looks on Gabriel’s and Triton’s faces as they swam to the throne room, he was sure they were thinking the same thing. 

Triton was fuming as they entered the room. He clutched his trident so tightly in his hand, Dean feared it was going to break or at the very least crack. “I can only think of one person that would hold enough ill will to take Castiel. Arthur,” Triton hissed in pure Alpha anger. “He lost the potential to gain a great deal of power when I nulled the agreement for him to mate Castiel.”

Dean looked from Triton to Gabe as he asked, “How the hell could he have gotten in and snuck Cas out without anyone noticing?”

“Well,” Gabe shrugged as he leaned against the wall. “Crowley is a powerful Sea Enchanter, and it would make sense that Arthur would have any number of spells at his disposal.”

Triton sat down on the edge of his throne as he groaned. “And Arthur knew Castiel’s heat was close. When we made the arrangements for him and Castiel to mate, I informed him when Castiel would be ready.” He placed his trident in the holder beside the throne before running his hand back through his hair and letting out a long distressed huff. “I guarantee that’s why he chose now to take Castiel, so he could claim him during his heat before Dean had the chance.”

Dean’s inner Alpha snarled at the thought of someone stealing his true mate from him. “Where,” Dean growled as he met Triton’s eyes. “Where would Arthur have taken him?”

“Home would be too obvious,” Triton mumbled as he scratched his beard, thinking. “The caves!” He called out as he sat up straighter on the throne. “The Crystal Caves, they use to play there as children. I would guarantee that’s where Arthur has taken him!”

“I know where that is.” Dean nodded, his fist clenched at his sides as he fought his inner Alpha from charging from the room and head first into danger. “Well, what are we waiting for let’s go!” Dean gaze flicked from Gabe to Triton, both Alpha’s faces set in worry.

“We can’t,” Gabriel murmured and shook his head. “That is, I can’t and neither can our father. We are bound by Atlantian law not to interfere.”

“What the hell are you talking about?” Dean rumbled, his inner Alpha clawing itself to the surface. He had a mate to save, to protect, he didn’t give a shit about laws. “He’s your son, goddamnit!” Dean yelled in frustration at Triton, his breathing ragged as he stared down the King.

“I know that!” Triton bellowed, his wide eyes full of fury and fear. “But son or not, King or not, I am a Mer of Atlantis and I must follow the rules laid down by those that came before me.” 

Dean’s jaw ticked and looked away from His Majesty. 

Triton’s gaze softened as he took in the younger Alpha. He could smell Dean’s anxiety, could see how his inner Alpha was riding him hard. He knew it was taking everything in the younger man not to dart off towards those caves halfcocked.

“Dean,” Triton sighed and waited until the Alpha met his eyes. “As badly as I want to intervene I can’t. This is a mating challenge and Atlantian law states it’s settled by the Alphas in the dispute.”

“Me and Arthur,” Dean growled as his fluke flicked back and forth impatiently. 

“What about Crowley?” Gabriel questioned as he pushed off the wall and swam over beside Dean as he looked at his father. “I could see him playing a part in this.”

“I could too.” Triton nodded before turning to Dean. “You are going to need a weapon.” He reached behind his back and brought forth another trident, this one also gold, but slightly smaller than his. He descended the throne and swam down in front of Dean. “Here,” Triton held out the trident for him to take.

“Thanks,” Dean took it, wide eyed and awed. The weight of the weapon was heavy in his hand as he gripped it. “I gotta know, how the hell did you do that! You just,” he waved his free hand in the air, “made this trident appear, like out of nowhere.”

“All warriors of Atlantis, their weapons are a part of them. They can call them forth anytime as needed.” Triton looked over at Gabriel and gave him a curt nod. 

Dean watched as Gabriel held out his hand, his arm began to glow and a slim silver blade slid into his hand. The Alpha flourished the blade with a smirk before the glow returned and the weapon was gone. Triton eyes slid back to Dean as he spoke. “Once you join the rank of Atlantian warriors, Rowena will bless you with the ability to also call your weapon.”

“Not that I don’t appreciate the trident, cause I totally do.” Dean licked his lips as he looked at the weapon. “But if that Crowley dude is there, he’s a Sea Enchanter, he’s got magic!”

“This trident,” Triton reached over and ran his fingers up the middle prong. “It was my very first, and it holds magic of its own. If Crowley is there, this trident will protect you. His magic won’t be able to touch you.” 

Gabriel gave Dean his best smirk as he slapped him across the back. “You got this Dean-o! Now, go! Rescue your Prince!” Dean nodded, seeing past Gabriel’s cocksure demeanor and straight into the face of a worried big brother. 

“Dean.” He turned to the elder Alpha, his mate’s father, and king. Triton placed his hands on both of Dean’s shoulders and gave them a squeeze. “Bring my son home.”

“I will,” Dean held Triton’s gaze, and for the first time since Dean met the elder Alpha he didn’t seem as terrifying—more like terrified. He was putting so much trust in him. And Dean was going to be damned if he would let him down, or Cas. 

Dean gripped the trident tighter, and raised his head high. “I promise you.”

Triton saw the look of determination and fire in Dean’s emerald eyes. “Be safe.”

  


  


Castiel groaned and slowly blinked into consciousness. He tried to stretch, to ease the twinge in his shoulders, only to realize he couldn’t move his arms. Panic squeezed his lungs, it made it hard to breathe. The panic continued to swell inside him as his eyes snapped open. 

His vision was blurry and his body ached as a wave of heat coursed through it. Castiel’s heart started racing as his eyes adjusted and he took in his surroundings. The Crystal Caves? What the hell was he doing in the Crystal Caves? He gasped as memories came flooding back. 

He’d been in his room laying in his nest with Finn and anxiously waiting for Dean to arrive with his answer, when there was a knock on the door. Excited that it was Dean, he raced over and pulled the door open. He was shocked to see Arthur on the other side. Castiel asked what he wanted and Arthur said he’d came to talk to him about what happened at the Rite. When the Alpha asked if he could come in Castiel shook his head and told him that it wasn’t a good time. He only had a moment to see the look of hurt that flashed across Arthur’s face before Crowley appeared beside his son and blew a grey dust in his face. The last thing he remembered before completely blacking out was Arthur muttering he would take good care of him.

“Well, look who finally decided to wake up.” 

Castiel _knew_ that voice, it was the unpleasant voice of his friend’s father. Crowley. The Omega turned his head towards the source and sure enough there he was, sitting on a large rock, with Arthur next to him.

A pang of hurt and betrayal hit Castiel hard in the chest at the sight of Arthur. Knowing that a man he had once considered a close friend had played a part in kidnapping him, taking him away from the castle, away from his Alpha. For what? What could they possibly have in store for him?

“Let me go at once!” Castiel demanded in his most authoritative tone.

“Yeah, we’ll get right on that Prince Castiel.” Crowley spat as he leered at the Omega.

“Why,” Castiel whispered. “Why are you doing this to me?” His gaze landed on Arthur, “I thought we were friends.”

“We are Castiel,” Arthur shifted on the rock. Leaning forward his fingers twitched in his lap nervously. “But I always thought we were destined to be more. That you cared for me the same way I di—”

“What kind of Alpha are you,” Crowley growled forcefully, cutting his son off. “I raised you better! Quit whining and be a _real_ Alpha, _take_ what you want!” 

“Yes, sir,” Arthur nodded curtly as he looked away from his father and Castiel, staring down at his fluke instead.

“Why am I here?” Castiel asked again as he struggled against his bonds.

“Why are you here?” Crowley let out a loud boisterous laugh. “Oh, that’s rich!” He got down from his perch and dashed toward Castiel, “You ruined everything! Turning Arthur down at your Rite! True Mate,” Crowley sneered, “you found your true mate, a _human_ true mate ha!” At Castiel’s gasp the Sea Enchanter curled his lips in distaste. “Oh yeah, Triton told me everything. Well,” Crowley rolled his eyes and waved his hand with a flourish, “Bad timing, that. But it doesn’t matter, not now. You see,” he leaned in closer to Castiel, “we want the power we deserve, the power that will be given to us once Arthur mates you.” He dropped his tone almost to a whisper, “And he will right when your heat is in full swing! And before that precious true mate of yours can rob us of what will be ours!” 

“No!” Castiel gasped and flailed in the nest, desperately trying to free himself. “I belong to Dean! No one else can have me.” He drew as far from Crowley’s leering face as his bonds would allow, “I will never be mated to anyone but Dean!”

“Castiel,” Arthur cautioned as glanced back up and met the Omega’s eyes. “I may not be your true mate, but I promise I will make you happy. I even made you a nest so you would be comfortable.”

“You could _never_ make me happy.” Castiel sneered at his former friend. “You are not Dean!”

“Dean. Awwwww,” Crowley mock cooed as he swam around Castiel and stared him down. “Your precious true mate? The one that’s not here? The one that’s not gonna rescue you in time before my Arthur claims you.”

Neither Crowley or his son heard or saw the former human enter the caves. They were too caught up in their own plan and were too confident in their own prowess to imagine anyone coming for Castiel, much less a magiced merman. Dean heard them taunting his Omega and it stoked his fire and resolve.

“That’s where you're wrong!” Dean snarled as he rushed further into the cave. 

“Dean!” Castiel cried out. “Thank the Gods!”

“Wha—” The Sea Enchanter barely had time to turn before being slammed against the wall by the other Alpha. Dean pinned him in place, his hand pressed to Crowley’s chest, and the trident to his throat. 

Dean glanced over to his mate. “You okay, baby?”

“Better now,” Castiel grinned at his mate. “I was so scared Arthur would claim me.”

“Not a chance in hell.” Dean returned Castiel’s smile. “You’re all mine, _only mine_.” Dean’s smile fell and he growled as he saw Arthur try to flee out of the corner of his eye. “You,” his hand moved from Crowley’s chest to grip his throat as he pointed the trident at Arthur. “Don’t even think about it.” 

“Okay,” Arthur held up his hands in a placating manner. 

“Over here,” Dean nodded to the wall beside Crowley. “Come join dear ol’ Dad.”

“Alright,” Arthur nodded and slowly made his way over, leaning back against the wall beside his father.

Dean moved the trident to his left hand, and placed it at its original position, pressed to Crowley’s throat. With a deep growl he balled up his right hand and punched Arthur in his nose. “That’s for trying to take my true mate.”

“Bloody hell,” Arthur cursed as he reached up and pinched his nose trying to stanch the blood flow.

“You deserved that! You deserve more than that!” Dean huffed as he leaned into Arthur’s space. “You act like he’s your friend yet you were going to mate him against his will.” His hand gripped Arthur’s chin tightly and forced him to meet Dean’s eyes. “You should consider yourself lucky I don’t kill you where you stand.”

“I’d understand if you did.”Arthur murmured as he went limp in Dean’s hold. “You’re right, I’d deserve it.”

“Piss poor Alpha,” Crowley scoffed. “Once again it’s all up to me.” Crowley muttered a few words, his brows furrowed when nothing happened. He cleared his throat and tried again. 

Nothing, again. Crowley’s eyes widened as he stared at the trident. “Is that Triton’s?”

“As a matter of fact it is.” Dean grinned as he pressed it more firmly against Crowley’s throat. “That wasn’t magic you were trying to use now, was it?”

“Fine,” Crowley hissed as his eyes narrowed. “You win! You win this mating dispute. Now take your mate and go.”

“Oh, I plan on it. But first,” Dean grinned ferally. “As recompense for me sparing your lives, the both of you are to leave Atlantis and _never_ return.”

“Okay,” Arthur quickly agreed.

“You can’t be serious!” Crowley wailed. “I refuse!”

“I’m very serious. Deadly serious,” Dean rumbled as he removed the trident from Crowley’s throat, and ran the left prong up his cheek. The Sea Enchanter hissed as the weapon dug into his skin. “You sure you want to refuse?” Dean asked as he pulled the trident back and watched a bead of blood trickle down Crowley’s cheek.

“Come on father, be reasonable.” Arthur whispered as he reached over and touched Crowley’s shoulder. “He’s letting us live.”

Crowley jerked free from his son’s hold and leered at both him and Dean. “Atlantis has lost its luster—letting humans in. Taking humans,” he scoffed “as mates!” 

Dean moved back, and let Crowley and Arthur pass. “Purgatory will be a better fit for us.”

“I don’t care where you go,” Dean stepped in from of Castiel, shielding him from Crowley, just in case the Sea Enchanter decided to take his chances and try something else. “Just don’t ever come back, because next time, it won’t be just a cut on the cheek. If you return, or try anything like this again, I _will_ kill you.” His glared over at Arthur, “Both of you.”

Arthur nodded once as he swam out the caves. Crowley hissed, “Don’t worry, I have no desire to ever set eyes on you again. We won’t return,” he turned with a sharp swish and followed behind his son.

“Dean,” Castiel moaned as he twisted in the nest.

“Cas,” Dean tore his gaze away from the retreating Alphas, and turned to face his mate. “I'm here, Sweetheart.” Dean dropped down beside Castiel and eased the Omega onto his side facing away from him and used the prongs from the trident to cut his mate’s bonds.

As soon as Castiel’s hands were free he spun round and wrapped his arms around Dean, knocking the trident from his hand. “Alpha,” Castiel purred as he nuzzled at his mate’s throat. “You came for me.”

“Of course,” Dean pulled back and met his Omega’s eyes. “I love you, Cas.”

“You love me,” Castiel whispered in awe.

“I fell in love with you the moment I heard your voice.” He leaned forward and pressed a chaste kiss to Castiel’s lips, murmuring against them, “I choose you baby. I want to stay here, in Atlantis, with you. I swear you will never see regret in my eyes. You are it for me.”

“I love you too, Dean. You’re it for me too.” Castiel pulled him back in claiming his lips, moaning as his Alpha slipped his tongue into his mouth and tugged him closer. 

The scent of slick and heat grew stronger the longer they kissed. The sweet smell was driving Dean’s inner Alpha crazy. The beast within was demanding that Dean mate and claim, that he mount and bite. That he make Castiel his.

“Cas,” Dean jerked back with a gasp. “Sweetheart, your heat is in full swing, and your scent is—” Dean trailed off with a low growl. “I want you so badly. I _need_ you.” Dean ran his hands over the supple mounds of his mate’s ass, a deep rumble resonated from his chest as Castiel arched into his touch. 

“Gods, yes, _please_ ,” Castiel purred as Dean rose up, still holding the Omega. The Alpha shifted Castiel in his arms as he carried him bridal style out of the cave towards home.

Dean smiled down at his mate. “Let's get back to the castle, to our nest, and make us official.”

**Notes for the Chapter:**

> Hope you enjoyed the chapter!
> 
> [ _**Graphics Masterpost created by ZephyrChrysalis here!**_ ](https://archiveofourown.org/works/15728604/chapters/36566784)


	7. Chapter 7

**Notes for the Chapter:**

> Big thanks to Ani-make-me-girl for beta’ing this chapter, and zephyrchrysalis for Alpha reading and providing art.
> 
> This last chapter is another long one!
> 
> And it’s my birthday so while you guys enjoy the final chapter I’m gonna enjoy a slice of birthday pie!
> 
> <3

  


**“I will love you**

**as the sea loves.**

**In gentle waves**

**and in**

**ferocious storms.”**

**Nick Frederickson**

  


  


“Cas,” Dean groaned as the Omega slammed him against his bedroom wall. The trident fell from Dean’s hand as he wrapped his arms around his Omega, pulling him flush against him. Dean craved the feel of skin on skin just as much as his heat crazed mate.

“You, me, nest, now,” Castiel panted in his Alpha’s ear.

Dean growled as he grasped his mate harder and lunged towards the nest. When they hit the sand the Alpha’s elbow knocked the nestside table, and a small lavender vial landed in the sand beside them. Dean furrowed his brows as he looked from the vial, to the table, where he noticed a piece of paper. Dean curiously reached up and grabbed it. His eyes immediately started skimming.

“Do you have to read that now?” Castiel whined, completely ignoring the small glass bottle as he leaned up and licked a stripe up Dean’s throat.

“Yeah, Cas,” Dean shivered at the warmth of his mate’s tongue. He reluctantly pulled back and met his Omega’s lusty gaze. “Now is the perfect time. I think you should really hear what’s written here before we go any further.” Dean cleared his throat and began to read.

  


  


“I do want kids, I really do. But,” Castiel picked up the vial and twisted it in his fingers. “I think I want some time with just me and you first.” He drew his bottom lip into his mouth as he looked into Dean’s eyes. “What do you think?”

“I want that too. I want romantic evenings, late nights making love. I want to have many adventures with you.” The Alpha grinned as he took the vial from Castiel’s hand and uncorked it. “Kids being one of them, just not now.” 

Castiel wrapped his hand around his mate’s and brought the vial to his lips. Together they tipped it up and the contents spilled down the Omega’s throat. Once Castiel had drank every drop, Dean tossed the vial aside. He rumbled deep in his chest as he looked down at Castiel. “My inner Alpha is clawing at me to claim you, begging me to _please_ you. So, Baby,” Dean nipped at his Omega’s mating gland, “Tell me what you want.”

“I want—” Castiel trailed off as he gripped Dean’s shoulders and flipped them. The Omega licked his lips as ran his hands down his Alpha’s strong chest. “I want to sing to you, need to seduce you.” Castiel purred, feeling the pull from his inner Siren as it urged him to tempt his Alpha, to ensnare him completely. 

“Gods! Yes,” Dean moaned as he stared up at his Omega. “Sing to me, My Beautiful Siren.”

Castiel twined their tails together before leaning down and kissing Dean once on the lips. When he moved back he met his Alpha’s gaze and began a haunting hum. He hummed as he slid down his Alpha and began to pepper tiny kisses along his lower abdomen right where his tail started. He felt his Alpha shiver under him. Castiel knew how sensitive this part could be on Merfolk and for Dean it would be a completely new sensation. He hummed again this time against his Alpha’s crease and then began to sing as he dropped small kisses and dipped his tongue into Dean’s naval.

“ **I swear to you I will always be there for you  
There's nothin' I won't do   
I promise you all my life I will live for you  
We will make it through**.”

Dean’s eyes glazed over as Castiel’s words made their way to his ears. His body immediately responding to his mate’s sultry tone. Dean rutted upwards against his Omega as his cock thickened, and his sheath gave way. 

“ **Forever, we will be,  
together you and me.   
Mm, when I hold you nothin' can compare.   
With all of my heart you know I'll always be  
right there**.”

The hazy feeling of his mate all around him made Dean’s head swim. It was like a high unlike any other, and something more addictive than any drug could possibly be. The Alpha’s skin tingled as Castiel scratched his fingernails up his chest and down his sides.

“ **I believe in us, nothin' else could ever mean so much.  
You're the one I trust.  
Our time has come, we're not two people,   
now we are one.  
Yeah, you're second to none**.” 

Castiel blood pulsed his in veins, his skin felt like fire was licking against it. He knew the only way to cool this inferno raging within him was with his Alpha’s touch, his bite, his seed. As the flames claimed him from the inside out, he undulated in Dean’s lap as he continued crooning the lyrics to his song of seduction. His breath hitched and he faltered slightly when he felt his cock slide against his Alpha’s. 

“ **Forever, we will be,  
together, a family.   
The more I get to know ya, nothin' can compare.   
With all of my heart you know I'll always be  
right there**.” 

Castiel kissed, caressed, and branded the words against his Alpha’s body, wanting them to remain there forever. The Omega’s hand slithered between them and he gripped Dean’s throbbing cock in his fist. He practically purred at the feeling of the hot hard flesh in his grip. As Castiel slid his hand slowly up and down his Alpha’s shaft he could feel slick seep from his hole, as his scales softened and parted, readying him to be mated.

“ **Forever we will be,  
together, just you and me.  
The more I get to know ya, the more I really care.   
With all of my heart you know I'll always be—  
And you know I really love ya, nothin' can compare.   
For all of my life you know I'll always be,  
right there**.” 

Castiel smiled up at his Alpha then whisper-sung the last words into his Alpha’s chest. As he looked back up, Dean’s pupils were lust blown. He was dazed, entranced from the song of his Siren. Dean rose, his eyes trained on his Omega’s lips. Castiel darted down and they clashed in the middle. The kiss was rough and passionate. All teeth and tongue, heat and fervor.

When the mates parted Dean leaned back in, pressing a soft kiss to his Omega’s jaw as he whispered, “I love it when you serenade me.”

“You give me a reason to sing.” Castiel purred, nuzzling against his Alpha’s mating gland where the heady scent of island driftwood and amber were the strongest. 

“Cas,” Dean writhed underneath Castiel as his Omega began to nibble along his jaw. The Alpha’s hands danced down the dip of his mate’s spine and gripped his ass. Castiel moaned loudly a Dean’s fingers gently pried his scales apart. Thick hot slick flowed from the Omega’s puckered entrance as Dean slipped two fingers inside his tight hole. 

“Alpha,” Castiel keened as he pushed back on Dean’s fingers taking them all the way inside his body. “More, Alpha. I want more.” 

“Feel good?” Dean grunted as Castiel fisted his cock faster. The Alpha dipped in a third finger and pushed deeper, fingertips rubbing that special spot that drove his Omega wild with want. 

“Oh! Dean!” Castiel cried out as slick gushed from him. The sweet scent of it infiltrated Dean’s nostrils, surrounding him with the tantalizing smell of coconut and shea butter.

“Cas, want you.” Dean groaned as his mate thumbed over the head of his cock, gathering the wetness that was beaded at the tip. “Need you,” the Alpha growled as he watched Castiel bring his fingers to his lips and sucked them into his mouth, cleaning the precome from them.

“Then take me.” Castiel leaned down and kissed Dean once before moving forward, gasping when Dean’s fingers slipped free from his body. He slid off Dean and lay down on his stomach in the middle of the nest. Castiel pushed his hips up scales parting wider revealing his slick entrance. He peered over his shoulder and met Dean’s eyes as he purred, “Claim me, Alpha.”

Dean rumbled approvingly at the way his mate presented for him. The Alpha shifted and draped himself over Castiel’s body. “So hot like this, Cas.” Dean scrapped his teeth over his Omega’s mating gland, loving how he quivered beneath him. The Alpha hummed as he rocked his hips back and forth, his cock sliding through the wetness between Castiel’s scales. “Wanna mate you so bad. But first,” Dean placed a kiss to the spot he would embellish with his bite, before he whispered in his mate’s ear. “I want to _taste_ you.”

“Oh! Gods!” Castiel keened as Dean kissed, sucked, and nibbled his way down his Omega’s spine, leaving teeth marks and blooming bruises that would decorate Castiel’s body days after his heat had passed.

The strong sweet scent of his mate’s personal bouquet was making his inner Alpha wild. At the feel of skin melding into silky scales Dean growled, knowing he was getting close to the intoxicating aroma. 

The Alpha’s hands cupped Castiel’s ass, and gently spread the scales, giving him a better view. The Omega’s entrance pulsated as slick poured out of him in rivulets. Dean leaned forward and swiped his tongue through the ambrosia. The Alpha groaned as slick coated his tongue, his eyes rolled back into his head at the delicious taste of his mate’s juices. One tiny sample and he knew he was already addicted, that he wouldn’t be able to get enough of Castiel’s sweet heady slick. 

Dean swirled his tongue around Castiel’s rim before pressing in. “Alpha!” Castiel cried out as Dean teased at his hole, alternating between licking long broad stripes over it, sucking at it, and pressing into it. Dean wanted more, _needed_ it. He gripped Castiel’s ass harder and delved in deeper.

Castiel keened and pushed his ass back against the Alpha’s face. Taking that as a challenge Dean growled against his Omega’s satiny scales before he licked and sucked harder, loving the feel of the excess slick he couldn’t swallow, leaking down his chin and staining his chest, marking him with Castiel’s scent. 

As Dean’s tongue swirled around the tight ring of muscle he pushed two fingers inside his mate’s hot hole using them to spread him open wider so he could get his tongue in further and chase his sweet taste. As the pads of Dean’s fingers brushed over Castiel’s prostate a fresh burst of slick poured from him.

Dean licked his lips and sat back. He watched hungrily as Castiel rocked back on his fingers. The Alpha’s hand and wrist was soaked from his Omega’s juices as he slipped in a third finger and brushed Castiel’s prostate.

"Please, Alpha, mate me,” Castiel pleaded as he glanced over his shoulder and met his mate’s lecherous stare. “ _Claim me_.” 

“Gods! Yes,” Dean groaned as he pulled his fingers free from his Omega’s body and used the excess slick to coat his throbbing cock. “Gonna make you all mine,” The Alpha rumbled as he positioned his erection at his mate’s slick hole.

Castiel’s nails dug into the sand as Dean entered him. He threw his head back, a loud trilling sound pouring past his lips as his Alpha’s hot length filled him. Castiel let out a soft purr when Dean was fully seated within him and flush against him. Dean’s beautiful large, thick cock made his heat toys look like tiny playthings.

He hummed in appreciation and rubbed his tail against Dean’s more vigorously.

“You like that,” Dean murmured.

Castiel couldn’t form words. He was lost in the throes of his own ecstasy. He flicked his tail against Dean’s again.

Slick pulsed from Castiel’s hole to help ease the way, as Dean began to move. “Alpha,” the Omega groaned and dropped his head onto his arms as Dean slid his cock out to the tip then thrust back in. Castiel’s cock hung hard and heavy from its sheath. Precome beaded at the head as Dean hit his prostate over and over. 

“Oh! Gods, yes, yes! Dean!” Castiel cried out from the overstimulation of it all as his Alpha picked up the pace.

Dean had wanted to go slow, to make their mating last for hours, but there was an inarguable sense of desperation in way Castiel pushed back into him, the way his skin felt like fire to the touch. Each keen was like music to him, every breathless gasp was just as enticing as the Siren’s song had been. It lulled him in, to mate and to claim what was his, and to do it right _now_.

Dean draped his body over his Omega’s as he rutted desperately into Castiel. “Fuck, Cas,” he panted into his mate’s ear. “Feels so good. I’m so close, Baby.”

“Oh! Dean,” Castiel gasped as he felt his mate grow and thicken with each thrust. “I need, I need—” he trailed off with a whine, heat coursing through him.

“I know, Sweetheart.” One hand gripped Castiel’s hip and the other slide down his Omega’s chest and enclosed around his rock hard cock stroking it in time with his thrusts. “I know exactly what you need.”

Dean snuffled at Castiel’s mating gland. They were both so close and the Alpha knew exactly what he needed to do to send them spiraling into the precipice of euphoria. Once Dean found the perfect spot, where his neck met shoulder he sunk his sharp teeth in. Castiel cried out as his blood filled Dean’s mouth. With one final thrust and the sweet taste of the crimson liquid Dean’s blossoming knot popped past his Omega’s rim catching on his inner walls and swelling to completion.

“Oh, Alpha!” Castiel keened as he felt the pulse and spasm of Dean’s cock filling him full with his Alpha’s hot, thick release, plugged deep inside his body. The Omega’s inner walls clenched and milked the Alpha’s cock, needing his seed to quell his heat. Castiel hummed blissfully as he felt another load pumping into him, his heat receding for the time being. The Omega shivered, knowing his mate’s release was going to be everywhere when Dean’s knot went down and was no longer holding it in place. Cas let out a breathy moan as he felt a small trickle slip past the knot and run hot down his tail. 

“Your turn now, My Sweet Omega, My Beautiful Siren.” The Alpha leaned forward and tilted his head, giving Castiel better access to his throat to seal their bond.

Castiel turned his head and nuzzled at Dean’s mating gland. He pressed a gentle kiss to the spot before biting down, tasting the coppery flavor of Dean’s blood as it flowed into his mouth. The Alpha growled and shoved his hips forward, more seed spilling from his cock as Castiel’s hole massaged his knot. The Omega quivered, his cock twitching as Dean gripped tighter and stroked faster. Castiel’s entire body felt like a live wire, overwhelmed with the pleasure of heat, mating, and being filled with his mate’s seed. 

“Dean!” Castiel cried out as his cock throbbed in Dean’s fist, spurting his hot release on his Alpha’s hand and the nest beneath them.

“That was fuckin’mind blowing.” Dean panted as he shifted, rolling them so they were laying on their sides. As soon as they were settled his arms wrapped around Cas’ waist holding him close. He caressed his mate’s tail with long slow strokes. He shivered as a tingle ran up from his dorsal fin. He’d have to ask Cas about that some other time. He sighed as he stroked his mate’s tail again.

“I have to agree with you there.” Cas slurred as he peered over his shoulder at his Alpha. “And to think, we have four more days ‘til my heat’s over.”

Oh, Gods,” Dean rumbled as he pressed a kiss to the fresh mating mark on Castiel’s shoulder. “We better rest while we can.”

“I agree,” Castiel purred as he snuggled back into his mate. 

Dean breathed in their combined scents. Their scents were perfect together. He wasn’t be surprised though, this was his true mate. Everything was perfect. He nestled into Cas’s neck and took in another breath as he gazed out at the manatee wafting passed their window. He fell asleep with the soothing aroma of happy mates wrapped around them.

  


  


Castiel hummed before cuddling back into Dean. The last four days had been amazing. A blur of songs of seduction and heat, of sex and love. The Omega’s body ached, but he cherished the feel. Castiel felt sated, loved, and completely owned by his true mate.

“How you feeling this morning, Sweetheart?” Dean asked around a jaw cracking yawn.

“Perfect,” Castiel purred as he rolled over in Dean’s arms and began to nuzzle at the bite he’d left on his Alpha. “What about you?”

“Unbelievable,” Dean growled as he grinned at Castiel before kissing him thoroughly. A loud knocking on the door had them parting.

“Can I come in?” Gabriel’s muffled voice came from the other side of the door. “I’m not gonna be scarred for life am I?”

Castiel and Dean chuckled as they called back in unison. “It’s safe!”

“Thank fuck!” Gabriel swung the door open and swam in. “Don’t think my fragile psyche could have handled seeing you two in another compromising position.” As Gabriel opened his mouth, a series of loud barks from the hallway was followed by one very excited sea lion flitting into the room and interrupting him.

“Finn!” Castiel called out and held his arms open for his pet. But the sea lion halted beside Gabriel. “Come here, Boy,” Castiel cooed. “I’ve missed you.”

Finn sneezed and shook his head. He snorted a few times before glancing over at the mates then up at Gabriel as he started barking in an argumentative manner.

“I know, I know,” Gabriel sighed as he patted the pups head. “It stinks in here.”

“Really?” Dean stretched in the nest before wrapping his arms back around Castiel. “I think it smells _amazing_ in here.” The Alpha drew in a deep breath and let it out slowly with a pleased hum. His inner Alpha was preening with the knowledge that anyone who set foot in here could scent how well he’d bred his mate.

“Dean-o,” Gabriel rolled his eyes and continued in his best deadpanned tone. “Your bedroom smells like this is where sex came to die.” The sea lion barked in agreement, before sending one last glimpse, and a couple petulant barks at the mates, before darting from the room.

“Finn,” Castiel pouted as he watched his retreating pet.

“It’s okay, Cas.” Dean ran his hand down his Omega’s back. “Your heat has passed. When you’re feeling up to it we can take Finn for a swim.” He chuckled, “And once our room has a chance to air out, you’ll see, Finn will be back and playing happily. Plus,” Dean’s gaze fell on the trident in the corner of the room, “I need to return your father's trident and explain what happened to him.”

Before Castiel could respond their attention was drawn to Gabriel who was yelling out into the hallway. “I hear ya, Finn. It absolutely reeks to high Heaven in here. I’ll join you as soon as possible! Then we’ll go raid the kitchen!”

Gabriel spun back around and started grumbling to himself. “Why am I always the one asked to deliver messages to these two. We have a massive number staff that could do it, but noooooo,” Gabriel carried on with his rant, “ _I’m_ the one that gets to risk seeing my little brother in compromising positions, and smelling the results of him and his Alpha doing the horizontal tango.”

“Gabriel,” Castiel snapped his fingers, instantly ceasing his brother’s bitching. “Focus! You said something about a message?”

“Father is waiting for you and Dean in the throne room.” Gabriel scrunched up his nose and turned, calling over his shoulder as he fled, “And now that I told you I can go elsewhere, where it’s safe to breathe!”

“So dramatic,” Castiel snorted as Gabriel slammed the door shut behind him. The Omega stretched his stiff muscles as he sat up, his eyes landing on a necklace on his nestside table.

“Oh, yeah, I made that for you.” Dean rose up on his elbow and rubbed the back of his neck nervously before leaning over Castiel and picking up the necklace. “Rowena lent me the tools, and her company, the day you left me to,” he paused and then grinned, “ruminate over everything in the courtyard.” Dean settled in the sand, leaning his back against the wall. “When I finished it I rushed up here to present it to you, and ask you to accept it, and me as your Alpha. But—” Dean trailed off with a shuddered breath.

“Hey,” Castiel whispered as he leaned back next to his mate. “You rescued me. I’m safe,” he nuzzled his Alpha’s jaw reassuringly.

“I swear,” Dean whispered back as took comfort in his mate’s touch. “I will _always_ keep you safe.”

“I know,” Castiel pulled back to meet Dean’s eyes, his baby blues sparkling. “Soooo, are you gonna ask me?”

Dean’s brows furrowed. “Ask you what?” The Alpha watched Castiel’s gaze dart from his face to the necklace in his hands, then back. “Ohhhh,” Dean’s eyes widened.

“Yeah,” Castiel nodded, smirking at his mate’s expression.

“Castiel,” Dean cleared his throat and sat up straighter. “Will you accept this gift,” he held up the necklace with a bright smile. “And me as your Alpha?”

“Gods, yes!” Castiel blurted as claimed his Alpha’s lips.

Dean smiled into the kiss, deepening it. As his tongue mapped the contours of Castiel’s mouth, his hands were busy placing the necklace around his mate’s throat. When the Alpha fastened the clasp he pulled back to admire his beautiful Omega adorned with his mating gift.

“It’s extraordinary,” Castiel murmured in awe as his reached up and ran his fingertip down one of the Angel Wing Shells before caressing the deep green malachite stone. “This jewel is stunning.”

“It was your mothers. Rowena gave it to me.” Dean took hold of Castiel’s hand in the sand beside him. “Now you will always have a piece of her with you, again.”

“Oh, Dean, I love it.” Castiel wrapped his arms around his mate and lowered them back down into the nest. He slid his tail against his mates as he smiled down at his Alpha. “I love you,” he purred as he kissed along Dean’s throat, slowly undulating against his Alpha.

“I love you, too,” Dean gasped and gripped his Omega’s hips, momentarily stilling his movements. Dean licked his lips as he met the lusty look in Castiel’s eyes, the smell of their combined arousal thick around them. “How pissed do you think your father would be if we were a bit late.”

“Well,” Castiel smirked as he rolled off Dean and pushed his ass up in the air, presenting for his Alpha. Castiel glanced over his shoulder and wiggled his hips, “I guess we’ll find out.”

  


  


An hour later Dean and Castiel rushed to the throne room. When they flung the door open three sets of eyes landed on them. Gabriel shook his head and mock gagged as they swam into the room. Rowena smirked at them as they darted past her to the steps leading up to the throne. Triton quirked a brow at them as he took in their disheveled appearance. There wasn’t a doubt in his mind what they had been up to.

Dean shifted nervously as he held out Triton’s trident. “Here’s your weapon back. Thank you for letting me use it. I would have returned it sooner, but, well—” Dean trailed off under the piercing gaze of Castiel’s father.

Sure Castiel was his mate now, and it’s not like Triton didn’t _know_ what they had been doing the last four days. But that didn’t mean he wanted to _talk_ about it with him. It’s bad enough he could still smell sex on them. Hell, and with the look he was giving them right now, he damn sure knows why they’re an hour late.

“You can place it on the marble dais by Rowena, for now.” Triton replied, his fingertips skimming down the trident at his side. Dean bowed and flitted over and placed it down gently, ignoring the way Rowena was impishly grinning, her brow rose as she noticed the bite mark on his throat.

Once Dean was at his mate’s side again, Triton cleared his throat and met the younger Alpha’s eyes. “First off, I want to thank you, Dean, for bringing my son home safely. Secondly—”

“We wanna welcome you to the family, Dean-o!” Gabriel blurted out, cutting off his father.

“As I was saying,” Triton narrowed his eyes at his eldest before looking back to Dean. “Welcome to our clan. Welcome to Atlantis, and welcome to the ranks of Atlantian warriors.” 

“Thank you,” Dean responded, the tone of his voice thick with emotion. Out of the corner of his eye he saw Castiel smiling as he bowed once again to the King.

Triton gave Dean a curt nod before speaking. “There is one thing I’m curious about.” He sat back and started to drum his fingers on the arm of his throne. “What happened with Crowley and his son? No one has seen them since the day you saved Castiel from the Crystal Caves.”

Dean took a deep breath and outlined everything that happened. He started from when he found the broken necklace in Castiel’s bedroom. His report was concise and concentrated on how when he made it to the caves he overheard Crowley’s threats to Castiel, and Arthur’s intention to mate him. 

“I told Crowley never to return, and that if he did, I’d end him.” Dean looked over at Castiel for a moment, “Arthur couldn’t run fast enough, but Crowley wasn’t.” Dean shrugged slightly, “I gave him a shallow gash across his cheek with the trident and repeated my warning. Finally, he left.”

He looked up at Triton, “I probably should have killed him right there, but I wanted to get Castiel out of there. He was already in heat.”

Triton nodded, “I see. Continue.”

Dean quickly summarized how he and Castiel made it back to the castle and halted his recount there. There was no need to go into further detail, because, well, everyone knew what happened. He looked up into Triton’s eyes and asked. “Did I do wrong by letting them live?”

Dean glanced over at Castiel who was watching him closely. The Omega immediately sensing his Alpha’s worry through their bond moved in closer and twined their tails together. Dean sighed, the knot in his stomach easing some. The worry that Crowley was off somewhere biding his time until the right moment to strike, faded some.

“No,” Triton answered drawing Dean out of his internal musings. “A great leader shows compassion, even sometimes to those that are undeserving.”

“Are any of you worried?” Dean’s eyes flickered everyone before stopping at the King’s steely stare. “Worried that one day Crowley will come back and use his magic to try and get revenge.”

Rowena began to chuckle and Dean turned to her. His gaze landed on the Sea Enchantress just in time to see Gabriel pick up the trident Triton had lent him and toss it to his aunt, who caught it with ease and finesse.

“Not at all,” she replied as she ran a crimson nail up the middle prong. “The trident has very powerful magic in it. The day you faced Crowley and you cut him, his blood seeped into the trident. Once the weapon sensed he was evil and his intentions to Atlantis were not pure, it stripped him of his powers forever.” She turned the trident in her hands, a smirk painting her lips. “A clever enchantment if I do say so myself.”

“Yes, Rowena,” Triton rolled his eyes. “We _all_ know you are very intelligent and quite powerful.” Before she had a chance to retort, he turned to Dean, “After realizing you have stripped him of his powers, the thing he held most dear, no, Dean, I’m not worried Crowley or Arthur will ever return.”

“Not to mention, Dean-o” Gabriel began as he took the trident back from aunt and laid it on the dais once again. “Pretty sure they know you will tear them to tiny bits and feed them to the sharks if they show their faces in Atlantis again.”

King Triton hummed in agreement before clearing his throat to gain everyone’s attention. “Now that you have chosen to remain among us, proven yourself a warrior by rescuing my son, the time has come for Rowena to bless you as a true Atlantian and a warrior. To make your weapon a part of you, give you the ability to call it forth as needed.” He stared down at the younger Alpha, “Are you ready?”

“Yes, Sir,” Dean answered without a hint of hesitation.

“Rowena,” Triton nodded at the Sea Enchantress. “If you would.”

“It would be my pleasure,” she smiled as she swam over to Dean.

“My Alpha,” Castiel wrapped his arms around his mate and gave him a chaste kiss on the lips before moving back beside Gabriel to give his aunt room.

“Ready,” Rowena asked as she raised her hands.

“As I’ll ever be,” Dean replied with a cocky smirk.

“Oh, yeah,” Gabriel grinned at Dean just as Rowena was placing her hands on the Alpha’s shoulders. “This part hurts like a bitch.”

“Wha—” was all Dean got out before a blood curdling scream tore from his throat. His whole body felt as if it was being ripped apart and stitched together piece by piece. But just as suddenly as the pain came, it was gone, leaving him hunched over, sweating, and breathing heavily.

“Dean,” Castiel whispered as he ran his hand up and down his Alpha’s back. “Are you okay?”

“Yeah,” Dean nodded as he blew out a deep breath and rose up. “I’m fine, Cas.” 

“Sure?” Castiel asked as he scented the air for any sign of his Alpha’s distress.

“Positive,” Dean smiled at his mate’s caring nature as he leaned over and kissed him.

“Gross,” Gabriel mock gagged as he looked over to his Father. “Isn’t there like a law or something about no kissing in the throne room?”

“No,” Triton shook his head, humming as he reached up and scratched his beard. “But maybe I should put one in place.”

“Big babys,” Rowena rolled her eyes. “I think it’s adorable.”

Dean blushed at the attention the little kiss had gained them. “So,” he cleared his throat, wanting desperately to change the subject. “When do I get to choose a weapon?”

“Dear boy,” Rowena tutted as she smirked at him. “That’s not how it works.”

“Okay then,” Dean crossed his arms over his chest. “How’s it work?”

“You don’t pick from here.” Rowena reached over and tapped his temple. “You chose from here,” she placed her hand on Dean’s chest.

“How,” Dean asked with furrowed brows.

“Simple,” Rowena grinned at him. “Close your eyes, clear your mind, and follow your heart.”

Dean nodded and closed his eyes as he took a deep cleansing breath. His fingers on his right hand twitched at his side and he tried to hold them still, but they moved again, more persistent this time. _Follow your heart_. With that thought he relaxed his arm, and within moments his hand shot up and reached behind his back like he’d seen Triton do twice before. Dean placed his palm between his shoulder blade, his skin tingled and heated, seconds later he felt the weight of a weapon his in hand. The Alpha opened his eyes and brought forth his chosen weapon.

A trident.

It was slender and silver, and in Dean’s hand it felt like an extension of his arm. He was able to wield it with ease the way he head seen Triton and Gabriel wield their weapons. There was no doubt in his mind that this was the weapon meant for him. 

As Dean gripped the trident tighter, he held it with honor. He glanced up at Triton and could have sworn he saw a hint of pride in his piercing eyes and a small smile grace his lips.

“Kiss ass,” Gabriel muttered teasingly, hiding it behind a cough. Everyone turned to him. “What?” He shrugged. “I’m just saying what we are all thinking. Dean-o got himself a trident just like father. You can’t tell me he ain’t trying to earn some _serious_ brownies points.” 

“Gabriel,” Rowena sighed and slapped him upside the head.

“You know it doesn’t work like that, it’s all about the person’s integrity.” She looked from Dean to Triton. “The weapon the magics has chosen for Dean has just proven that Dean and Triton have a lot of the same virtues.”

Triton gave Dean a curt nod before he spoke. “Which only confirms the decision I came to last night was the correct one.”

“What decision, Father?” Castiel asked as he threaded his arm through his Alphas.

“That when the time has come for me to step down, you,” he pointed to Dean. “Will take my place and rule over Atlantis.”

Castiel and Rowena gasped as Dean sputtered, “What!” His eyes flickered across everyone’s faces before stopping on Triton’s eldest son. “What about him,” he nodded towards Gabriel. “Shouldn’t he be the one to take your place?”

Before Triton could answer Gabriel beat him to it. “Hell no!” The Alpha shook his head frantically. “I’ve _never_ wanted that kind of responsibility, and father’s always known that. So,” Gabriel slapped Dean on the back. “Think you can handle it?”

Dean looked from Triton to Castiel, “And your other son? My mate, is he not eligible?” He narrowed his eyes as he challenged the king, “Is it because he is a Omega?”

Triton held his hand up to forestall Cas’s protest and his lips lifted in a smile, “Not at all, Dean.” He gazed lovingly at his younger son and swung his gaze back to Dean, “Castiel is a Siren, and so, someday he will lead them. He cannot do both.”

Dean nodded and holding his trident at his side, he bowed before looking up into His Majesty’s eyes. “Then I’d be honored.”

“I’m so very proud of you.” Castiel placed a kiss to Dean’s cheek as he whispered, “I’m _honored_ to be your mate.”

Triton watched as his son smiled at his Alpha with such love and the look he was giving Dean reminded him so much of how his sweet Cordelia would gaze upon him. Before his memories could swallow him whole he clapped his hands together and exclaimed, “Excellent!” 

He leaned forward on the throne and stared at the younger Alpha. “I see great leadership skills in you, and I respect the decision you made allowing Crowley and Arthur live. I have no doubt with a little guidance you will make a wonderful king. Now,” he nodded to Dean’s trident, “Put your weapon away, we have another matter to discuss.”

Dean took a deep breath and draped the trident over his shoulder, as soon as the metal and his palm made contact between his shoulder blades he felt the weapon become one with him.

Triton swam from the throne and joined the others. He glanced at Rowena, who nodded, before turning to Dean and Castiel. “Rowena informed me she told you about the spell she could place on your necklaces.” 

“What spell?” Castiel whispered as he reached up and gripped one of the Angel Wing Shells on his necklace.

“Castiel,” Triton turned to him. “You are so much like you mother, so curious and fascinated with life on land. I want you to live and love to the fullest, to try things you’ve only dreamed about, and to do so I have to let you go.” He reached up and cradled his son’s face in his hands. “Your Aunt can enchant your necklace and Dean’s so that you can walk on land. See the world like I know you have always wanted.” Triton ran his hand back through his son’s hair before letting them fall to his sides.

“Really?” Castiel asked wide-eyed as he looked from his father to aunt.

“Yes,” Rowena nodded. “If you want to experience life on land, I can do it.”

“Dean,” Castiel spun to face his mate. “Can we?”

“It’s all up to you, My Omega.” Dean grinned at the look of pure enthusiasm on his mate’s face.

“Oh, my Gods, yes! Yes!” Castiel smiled back as he flung himself at Dean, the Alpha caught him with a huff of laughter. He squeezed his mate tighter, overwhelmed with happiness, until a thought occurred to him. “Wait,” Castiel drew in a sharp breath as he let go of Dean and turned back to his father. “I can’t. Atlantis is my home. I can’t leave it forever.”

“You’re joking right?” Gabriel burst out laughing and flung an arm around both Dean and Castiel’s shoulders. “Cassie,” he looked over at his little brother. “You really think we’d let you up and leave us forever?” Gabriel pulled Castiel in closer. “Not a chance in Hades.” Gabriel dropped his arms from the mates and motioned to Rowena with a flourish. “Auntie Ro, tell him all about the spell.”

“As I told Dean, it reads your intentions.” Rowena began to explain. “You go to the surface with the want in your heart to be on land, your tail turns to legs. You enter the water wanting to come home, your legs turn to tail once again.”

Castiel let out a relieved sigh. “So we can come home whenever we want.” 

“Yes,” Triton nodded and he chuckled as he looked at the pair, “and I want you two to return as often as possible.” He plopped down on one of the steps to the throne, “But,” his voice became serious and he honed in on Cas, “in between the many adventures I’m sure you are going to plan, I’d like you to keep in mind that there is much for Dean to learn.” His Majesty’s eyes slid over to Dean’s. “I’d like to start Dean’s training soon so that he can learn to rule wisely when the time come.” He looked from Dean to Cas, “If this is agreeable, Rowena can get started on the spell right away. So,” Triton grinned, “are those terms acceptable?”

Dean and Castiel side-eyed each other, both of them smiling. “Yes,” they answered in unison.

  


  


It took a week for Rowena to gather all the ingredients for the spell. On the morning of the seventh day she met Castiel and Dean in the throne room. Of course, Triton and Gabriel were also there, wanting to spend as much time with the mates as possible before they embarked on their grand new adventure.

As she swam into the room, Finn flitted past her and launched himself in Castiel’s arms. The Omega smiled and ran his hand down the slope of his pet’s back. Finn had been especially clingy ever since Dean and Castiel had decided to spend some time on land. The sea lion followed them everywhere, and at night wiggled between them in the nest. It was as if Finn _knew_ they were going to be leaving soon.

Rowena came to a stop in front of the mates with a huge grin. “You boys ready?” She held up a small silver vial and shook it.

“Yes,” Castiel nodded, Dean chuckled at the scent of pure excitement rolling off his mate in waves.

Finn whimpered in his arms and Castiel squeezed him tighter as he looked at Gabriel with wide pleading eyes as he asked. “Will you take care of Finn while I’m gone?”

“Fuck no,” Gabriel shook his head and crossed his arms. “He hates me and after a week without you he’d be driving everyone in the castle crazy. So,” he nodded over to his aunt.

Rowena held up a dog collar. A little silver bone dangled from the middle with Finn inscribed on it. “For Finn.” She handed it to Castiel. “We all knew it was breaking your heart to leave him behind. Go on,” she motioned, “you can put it on him, he won’t change until you reach land.”

“Thank you,” Castiel sniffled as placed the collar around the sea lion’s throat. He looked up at Dean, “This is okay, right? Us taking him, too?”

“Yeah,” Dean smiled as he patted Finn on the head, “the lil’ guy has grown on me.”

“Now,” Triton glanced to the vial in Rowena’s hand. “Time to spell their necklaces.” He smirked at the mates. “Since they refused to take them off while you enchanted the ones for Dean’s family.”

“You know how important mating gifts are.” Rowena rolled her eyes playfully at Triton as she uncorked the vial. “How many times have you taken off the Wentletrap shell bracelet Cordelia gave you?”

“That’s not the point,” Triton mumbled before huffing at Rowena, “don’t you have some magic to do?”

The Sea Enchantress cackled as she tipped the contents on the vial into her hand. Setting the empty glass bottle on the dais, she rubbed her hand together, coating them in a shimmering white liquid. Rowena smiled lovingly at them before running her left hand over Castiel’s necklace, the right over Dean’s covering them completely while muttering a few words under her breath. Just as she finished the necklaces glowed bright gold for a few moments before fading back to normal.

“All done,” Rowena replied cheerily. “Oh!” She reached for the three necklaces on the dais and handed them to Dean. “For your family. They are our family now, and welcome in Atlantis anytime. We would love to meet them.” She leaned into him, “I want to see them at your mating ceremony, and I’m sure it will be soon.”

“Really soon,” Triton added. “Ellen, the head of kitchen staff, is already in the process of planning your mating celebration. I expect your family to attend. As they are our family to now.”

“Yes, Sir,” Dean agreed and nodded because no way in hell was he going to tell him ‘no’. He wasn’t even sure if that was possible. Nope, he’ll make it happen.

“You two crazy kids ready to get this show on the road?” Gabriel asked as he poked both Dean and Castiel in the side. “We ready to head to the surface?”

“Your all going?” Castiel looked from his father to his aunt to his brother.

“Hells yeah!” Gabriel crowed with an impish smirk as he pulled his little brother into a headlock, and started ruffling his hair. “I got ten diamonds riding on Cassie here face planting when he tries to use his legs for the first time.”

“Let me go,” Castiel twisted in his brother’s grip and drew up his tail to fin-slap Gabriel. 

“Boys,” Triton sighed as he pulled his sons apart. “It’s time to go.”

As they swam from Atlantis and to the surface, the feeling was bittersweet for Dean. Though he’d only been in Atlantis for a little over a week it had become home. He would miss their little nest, the mornings spent hanging out with Castiel and Gabriel in the courtyard watching the younglings play. The lunch dates at Rowena’s, dinner in the evening with everyone. And their nightly swims, he’d really miss those. 

When they broke the surface at Dean’s special spot, the place where he first met Castiel, he couldn’t help but to smile. It was also where they ended up during most of their nightly swims. And when he looked back at Castiel he was smiling too. 

A loud bark drew everyone’s attention to Finn who was swimming towards the beach. “Watch,” Rowena whispered as Finn reached the shore. In a blink of an eye they were no longer staring at a sea lion. Finn was now a chocolate lab pup. He barked and shook off the water before plopping down on the sand and waiting for Castiel and Dean.

“Soooo,” Gabriel sighed as he looked at the mated pair. “I suck at goodbyes, so I’m not going to say goodbye. Instead—I’ll see you two soon.”

“Yeah, you will,” Dean nodded as Gabriel pulled them both into a hug.

Rowena swam up to them next. She looked to Dean first with a smirk. “You’re not so bad for a land Alpha.”

“Thanks, you’re not so bad for a Sea Witch,” Dean deadpanned as he pressed a kiss to her cheek and hugged her tight.

“Enchantress,” Rowena corrected, sniffling as Dean let her go and she turned to her youngest nephew. “Come here,” she held out her arms and Castiel swam into them. “I love you, Castiel.”

“I love you too,” Castiel hiccuped, tears filling his eyes. “Thank you for everything, Aunt Rowena. Especially for bringing Dean into my life.”

“You are so very welcome.” She pressed a kiss to his forehead. “Have fun, but do visit often.”

“I promise,” Castiel swore to her before he pulled back and shifted to face his father who was talking to Dean. 

His father as he was talking to his mate. Dean looked happy too, not scared like he’d been of Triton when they first met. Castiel couldn’t hear all of their conversation since they were leaning in close to each other and speaking softly. But after a few minutes Dean nodded and drew back, he held out his hand as if to shake the king’s hand. Castiel grinned as Triton shook his head and pulled Dean into a hug. The Omega’s heart filled with happiness as he heard a muffled ‘see you soon, son’ from his father. He knew his father accepted Dean into Atlantis and called him ‘family’ but this was true confirmation.

Dean moved back, giving Castiel room to say his goodbyes to his father. Castiel glided over to Triton and the two stared at each other for a moment, neither knowing what to say.

“This is harder than I thought it would be,” Triton said, breaking the silence between them.

“It really is,” Castiel whispered, tears streaming down his cheeks.

Triton reached up and wiped them away. “I’m so proud of the man you have become, Castiel. And that Alpha of yours, he’s a good man.” He smiled warmly at his son. “After you two have your adventures on land and return to Atlantis, I have no doubt the pair of you will rule Atlantis with honor and fairness.” He pulled his son in and hugged him tightly before reluctantly letting him go. “Your mother is smiling down on you today,” he whispered with watery eyes. “Go, live and love to the fullest, like she did every day of her life.”

“I will,” Castiel nodded before turning to Dean.

“Ready,” the Alpha held out his hand.

“Ready,” the Omega parroted as he threaded their fingers together.

The mates swam towards the shore and as soon as their flukes touched the sand they both gasped. They felt a tingling sensation in their tails as it split and turned to legs. Dean and Castiel walked towards the beach hand in hand. As soon as they were thigh deep in the water Dean realized they had boxers on. The Alpha mentally thanked Rowena for her foresight to add that into her little spell. Being naked in front of his mate’s family was definitely not something he ever wanted to experience.

When they reached the shore the Omega wobbled as he walked on land for the first time, but he didn’t fall. He grinned out at Gabriel as he yelled, “I didn’t fall!”

“Damnit! I’m out ten diamonds!” Gabriel shouted back. “Have fun! And don’t do anything I wouldn’t do!” He waved at the mate pair before disappearing underwater.

“Grand nieces and nephews, I want them!” Rowena exclaimed. “And I better be the first to know when you catch!”

“You will be!” Dean and Castiel hollered in unison.

Rowena smiled and waved before flitting away.

“Take good care of my son, Dean!” Triton called out to Dean before looking at Castiel and saying, “I love you, Castiel!”

“I promise, Sir!” Dean declared with a curt nod.

“I love you, too!” Castiel cried out as he blew a kiss to his father.

Triton waved goodbye before diving under, his goldenrod yellow tail shining in the sun moments before disappearing out of sight.

Dean and Castiel stared out at the Sea, the tranquil moment being broken by a series of barks at their feet and Finn’s warm wet tongue lapping at Dean’s ankle. The Omega smiled at Dean before taking a step, his knees giving a little and the Alpha’s arms shot out and caught him before helping him up right.

“I love legs!” Castiel giggled as he touched his thighs. “They may take a little getting use to but I love them!”

Dean smirked as he checked out his mate. The Alpha licked his lips as he stared at Castiel’s round supple ass, thick runners thighs, and firm calves. “I can’t wait to feel them wrapped around me.” 

“Dean,” Castiel gasped, his cheeks stained red with arousal.

“I love you,” Dean growled as he pulled his mate flush against him, one hand wrapped around his the lower back, the other cradling his cheek as he kissed Castiel while the water lapped up around their feet. When Dean broke the kiss he smiled brightly. His fingertips caressed his Omega’s cheek as he whispered, “I can’t wait to show you the world.”

  


  


Watching Castiel take his first walk on the beach was more exciting that Dean would have expected. His laughter as it echoed down the beach when he ran—Finn, of course, hot on his heels. The looks of admiration that Castiel got from women and men alike just made his heart race all the more, because they wanted Castiel, but Dean had him.

“The sand squishes!” Castiel exclaimed and Dean chuckled. 

“I know.” Dean clasped Castiel’s hand, “Let me show you my house.” 

Dean never thought he’d get to show Castiel his home. And it gave him a special feeling to know that they could share this home and share Castiel’s nest. “This,” Dean swung open the door, “is our land nest.”

Castiel walked in and grinned. “It’s so you.” He lightly touched some of the shells that were on the shelf in the living room. He spun around, “Where’s Baby? Can we go for a ride in her?”

Dean beamed and he grabbed the keys off the table where they were just waiting for him. He’ll never forget the joy on Castiel face as they took Baby out for their first of what would be many rides. They drove for several hours before returning to Dean’s cottage. They only had the one night before they had to leave for California so Castiel could meet his family. And that night held a lot of firsts, and watching Castiel’s reactions was always astounding. He was introduced to take-out pizza and beer. Television. And face-to-face sex. It was their first time being able to make love and see into each other’s eyes. The look of pure adoration in Castiel’s eyes as he wrapped his legs around Dean’s waist. The way his thighs squeezed the Alpha tighter as Dean thrust into him over and over until his knot blossomed to completion. How Castiel’s hands gripped Dean’s ass pulling him in deeper as he spilled his seed into his Omega. Castiel following directly behind, painting their stomachs in stripes of hot come. That was definitely something Dean would never forget.

Their first plane ride was a memory that Dean would lock away and remember forever. The look of awe on Castiel’s face as the plane soared through the sky to the States. His eyes darting out the little window, to Dean’s face then back again with a smile so wide Dean was sure his cheeks had to be aching. 

Dean was just as excited though. He couldn’t wait to reach California so he could introduce his true mate to his family. And to invite them to Atlantis for their mating celebration, which happened to be only seven days away. Dean sincerely hoped a week was enough notice for them all to be able to come. But when Triton had come to them with the set date before their trip to California, there was no way in hell Dean was going to try and get him to change it. 

Later that evening they were all at Bobby’s house enjoy take out Chinese and red wine, the conversation flowing as much as the alcohol. And just as Dean had predicted everyone had been thrilled to meet Castiel, and fell in love with him instantly. 

Everything had been going perfectly until Jess asked them how they’d met. When Dean recounted the whole tale to them everyone was speechless, as time ticked on the more uncomfortable the silence got. A good five minutes later the quiet was finally broken with Jess exclaiming she knew it, knew Merfolk were real. Sam and Bobby on the other hand were ready to check the mates into the nearest psych ward.

Dean argued with Bobby and Sam for well over an hour that they were not insane. He tried to get them to understand that if they would come back to his home, they could prove it. 

Finally, while Bobby and Sam were discussing which mental institutions would best suit the mated pair’s shared illusion, Dean booked everyone a flight to Nassau for a two week vacation.

They arrived in Nassau late so Castiel and Dean decided to wait until the next morning to show Bobby and Sam that Merfolk were, in fact, real. They presented the three with their enchanted necklaces and while they thought they were attractive, still did not believe they had any sort of special powers. Dean refused to continue to argue, and told them that in the morning they’d change their tune. And they did exactly that! After a hearty breakfast, Dean and Castiel let Sam, Jess and Bobby down to the water’s edge. They indulged in their own little ceremony. Castiel handed the necklaces to Dean who put the appropriate one around each of their necks. The spell was the same, but Rowena had uncannily captured the personality of Sam, Jess and Bobby, just from their talks. To this day, Dean will never forget that first time Bobby, Sam, and Jess stepped out into the Sea. Every opportunity Dean got over those first two weeks to say, ‘I told you so,’ he took it.

His family had loved Atlantis and were welcomed like royalty. Sam fell in love with the Atlantian library and spent many hours in there devouring the books. Jess spent most her time roaming around the city and chatting up the Merfolk and learning how to barter. Bobby, he became enthralled with their culture and way of life. Triton spent a fair amount of time with him explaining their history, heritage, and the laws of Atlantis.

Castiel and Dean’s mating ceremony had been wonderful. Lots of food, lots of celebrating, and lots of wine. It had been a night of fun and family, of love and laughter. The mates could not have been happier. They had all their family with them in their home, in Atlantis.

Before they knew it though, the two weeks were up, and Sam, Jess, and Bobby had to get back to the states, back to their lives. Dean and Castiel accompanied them when they left Atlantis and a few days after Dean’s family caught a plane home, the mates were planning their first romantic trip of many.

  


  


Over the next five years, Dean made good on his promise to show Castiel all the wonders the world had to offer. Castiel spent time, not only enjoying, but also photographing and chronicling their trips to add to the Atlantis library when they returned. Their leave-taking this time had been a bit more emotional—everyone knew it would be longer in between visits.

Paris had been amazing. They spent their time browsing shops, sitting at little cafes people watching. Touring the Louvre and admiring the priceless art. But their visit to the Eiffel Tower had been the highlight of that trip. The top of the tower offered some of the most beautiful views of the city, and the look on Castiel’s face as he looked out over the city had been breathtaking.

From Nice they continued onto Switzerland, to Germany and Austria. They took a break and headed off to Spain and Portugal before having to return to Atlantis for Cas’ heat. They only stayed a week in Atlantis before taking off to explore more of Europe. 

They spent a few weeks combing the streets of London and then taking in the English countryside before crossing the channel, by boat, no less to head off to Italy.

A tour of Italy, from top to bottom had been amazing. Each region of the country distinct, beautiful, inviting, and wonderful in its own way. In Verona Castiel dragged Dean to an ancient Roman amphitheater built in 30 AD. Dean bitched and moaned the entire time, not being a fan of the opera and all. But after he watch a performance of Romeo and Juliet in that age-old acoustically astounding venue he was reluctant to admit it wasn’t half bad.

In Venice they took a gondola ride. Castiel laughing the entire time as Dean serenaded him, badly. After the ride they strolled the streets stumbling upon endless craftsmen, artisans, markets, cafes, churches, palaces, galleries, theaters.

Rome had been the most memorable part of their trip to Italy. The Colosseum, the Forum, and the Pantheon were works of architectural art. Perusing the Vatican, the Capitoline Museum and the Borghese Gallery left them awestruck. That city was an inherent beauty set on seven hills.

When they returned from touring Greece and it’s islands the first thing they did was head to Atlantis. They had missed their nest, their home. They had also missed their family. Everyone had been thrilled to see them hugging them both tightly and Triton demanded to hear all about their trips at dinner that night. They spent a month in Atlantis, waiting until Castiel’s quarterly heat had passed before planning their next trip.

Iceland had been magical. Definitely one of the best trips they went on. It was astounding seeing active volcanoes, and its mountain ranges with colors so pure and plentiful they seem to be painted with watercolors. Exploring the ice caves and otherworldly rock formations had been unbelievable. But the part of the trip Dean would never forget was the hike they went on to get a spectacular views of the aurora borealis. They ended up making love and tied at the top of a mountain watching the bright vibrant lights dance in the nights sky. From there they spent time in Norway and Sweden. Then from Finland they flew to St. Petersburg and the Hermitage. They made the most of the three months they had before Cas’s heat would hit again.

But no matter where they went, how many trips they took, the wonders they saw, the beauty and magic of those places didn’t hold a candle to that of Atlantis.

And shortly after the fifth anniversary of their mating, when Castiel’s heat was due, they made their way to Atlantis, to their nest. The only place they rode out Castiel’s heat. Once they were in Castiel’s room, there on the nestside table, like always, was the potion Rowena made for him. This time though, Castiel didn’t take it. They were ready to start trying for a youngling. 

Exactly a month later, towards the end of August, Dean and Castiel were overjoyed to find out that Castiel had conceived after only one try. 

Less than a month after the mates found out Castiel was with child the sea called them home, and Dean knew in his heart it was for good this time. In many ways it reminded him of the pull to buy the little cottage in Nassau. 

Within two weeks Dean had signed the cottage over to Bobby, and Bobby added in his will that when he passed the cottage would go to Sam and Jess. They wanted to keep the home within the family, give Sam and Jess a place to vacation, eventually live, and Bobby a place to retire. They all still had the necklaces Rowena made and were welcome in Atlantis anytime. And with Bobby retiring in the next few months Dean was really hoping he’d make use of the cottage and his necklace, visiting them often. And he did, he ended up moving there.

As the months passed Bobby ended up spending more and more time in Atlantis than on land. Dean was thrilled, overjoyed to have him there, Bobby seemed genuinely happy too. He also seemed to enjoy spending a lot of time in the castle kitchen. And one night fetching Castiel a midnight snack, Dean found out why. 

Castiel had been craving pie during his pregnancy, which tickled the hell out of Dean because that gave him an excuse to eat more pie. 

As Alpha was sneaking into the kitchen to steal one of Ellen’s pies he saw something that made his jaw drop. Bobby and Ellen making out like two horny teenagers. Dean quietly grabbed the pie off the table and laughed the whole way back to their room.

Two months after Dean and Castiel returned to Atlantis for good Triton stepped down as King, passing the crown to Dean. Triton told the younger Alpha his time as King had drawn to a close, and he was fine with it. He smiled and said he was happy, that he wanted to use his free time to spoil his grandchildren when they were born. Triton also told him he knew in his heart Dean was ready and would rule Atlantis with pride. That Dean would be a fair and just King.

Castiel went into labor in early March just after the moon jellies had came out for the night. His labor was long and hard, and lasted well into the next day. But with Dean by his side, holding his hand, being his rock, he made it through. The Omega gave birth to a healthy set of twins. And once Dean and Castiel laid eyes on their son and daughter for the first time they were instantly head over heels in love.

That night as the mate’s lay in their nest, nuzzling and trading ‘I love yous’ while Castiel cradled their son, and Dean held their daughter, the Alpha felt complete. This was where he was meant to be, in this nest, with his mate and younglings. Atlantis was always meant to be the place he ended up calling home—what the Gods had planned for him all along. A smile spread across Dean’s lips as he thought back to that fateful day, and for over a millionth time since he and Castiel had mated he found himself thinking just how damn lucky he was that this beautiful Siren chose him to sing into the sea.

  


  


Dean glanced down at their son and daughter, who were fast asleep. His eyes flickered up to Castiel and the Alpha placed his finger over his lips. Castiel nodded as he and Dean eased their way out of the nest and slowly made their way towards the door, quietly shutting it behind them.

Out in the hallway Castiel took his mate’s hand and smirked over at him as they swam towards their bedroom. “I’m glad you keep the mating parts in the story PG, even though I know by the look on your face you’re thinking about the triple x rated version.”

Dean snorted as he gave his Omega’s hand a squeeze. “They won’t be able to hear the uncut version until they are at least sixteen.”

“Bite your tongue,” Castiel shook his head as he paused outside their bedroom. “You know they will never wanna hear such things about their parents.”

Dean chuckled as he backed Castiel up against the door and wrapped his arms around his Omega’s waist. Dean leaned in and pressed a kiss to Castiel’s lips before resting his forehead against his mate’s and whispering, “Will you sing for me tonight, Cas?”

“I will gladly sing for you tonight,” Castiel twined their tails together, murmuring against Dean’s lips, “and every night here after.”

  


  


**Notes for the Chapter:**

> Hope you enjoyed the fic!
> 
> [ _**Graphics Masterpost created by ZephyrChrysalis here!**_ ](https://archiveofourown.org/works/15728604/chapters/36566784)


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